British origins (Leslie et al. 2015)

The long-awaited paper on the People of the British Isles has just appeared in Nature. I will update this entry with more information.

UPDATE:

The authors write:

Consistent with earlier studies of the UK, population structure within the PoBI collection is very limited. The average of the pairwise FST estimates between each of the 30 sample collection districts is 0.0007, with a maximum of 0.003 (Supplementary Table 1).

These are extremely small differences in the European (let alone global) context. So, the British are, overall, a very homogeneous population. This is what led the researchers to use methods such as ChromoPainter/ fineStructure/ Globetrotter that can squeeze out fine-scale population structure by exploiting linkage disequilibrium. Thus, the authors are able to detect 17 main clusters of the British.

Most of the clusters are geographical, but some span different regions (e.g., the "yellow circle" cluster). The elephant in the room is the "red square" cluster which spans Central/South England. The authors write:

There is a single large cluster (red squares) that covers most of central and southern England and extends up the east coast. Notably, even at the finest level of differentiation returned by fineSTRUCTURE (53 clusters), this cluster remains largely intact and contains almost half the individuals (1,006) in our study.

The authors then tried to infer the ancestry of the British clusters in terms of continental European clusters, which is to be published separately. In the plot on the right, you see the British clusters (columns) and their continental European sources (rows). The authors observe that clusters that are widely represented in Britain are likely to be older, while those that are missing in some populations are likely to be younger, because they didn't have the chance to spread across Britain. For example, a couple of Norwegian clusters are strongly represented in the Orkney islands, and these are likely to reflect Viking colonization.

The authors draw conclusions on several historical episodes of British history. The big one is the extent of Anglo-Saxon ancestry:

After the Saxon migrations, the language, place names, cereal crops and pottery styles all changed from that of the existing (Romano-British) population to those of the Saxon migrants. There has been ongoing historical and archaeological controversy about the extent to which the Saxons replaced the existing Romano-British populations. Earlier genetic analyses, based on limited samples and specific loci, gave conflicting results. With genome-wide data we can resolve this debate. Two separate analyses (ancestry profiles and GLOBETROTTER) show clear evidence in modern England of the Saxon migration, but each limits the proportion of Saxon ancestry, clearly excluding the possibility of long-term Saxon replacement. We estimate the proportion of Saxon ancestry in Cent./S England as very likely to be under 50%, and most likely in the range of 10–40%.

Two other details are the lack of Danish Viking ancestry in England:

In particular, we see no clear genetic evidence of the Danish Viking occupation and control of a large part of England, either in separate UK clusters in that region, or in estimated ancestry profiles, suggesting a relatively limited input of DNA from the Danish Vikings and subsequent mixing with nearby regions, and clear evidence for only a minority Norse contribution (about 25%) to the current Orkney population.

And, the absence of a unified pre-Saxon "Celtic" population. What seems to unify "Celts" is lower levels/absence of the Saxon influence, rather than belonging to a homogeneous "Celtic" population:

We saw no evidence of a general ‘Celtic’ population in non-Saxon parts of the UK. Instead there were many distinct genetic clusters in these regions, some amongst the most different in our study, in the sense of being most separated in the hierarchical clustering tree in Fig. 1. Further, the ancestry profile of Cornwall (perhaps expected to resemble other Celtic clusters) is quite different from that of the Welsh clusters, and much closer to that of Devon, and Cent./S England. However, the data do suggest that the Welsh clusters represent populations that are more similar to the early post-Ice-Age settlers of Britain than those from elsewhere in the UK.

Unfortunately, the authors have decided not to make their data publicly available. This is very unfortunate, and will keep this research out of the hands of many people who would be interested in it and who would be interested in analyzing this data. I can already guess the disappointment of people of British ancestry from around the world who have a genealogical interest in tracing their British ancestors to particular areas of the UK. Apparently, the data is deposited in the EGA archive, access requires red tape, and is apparently limited to institutional researchers. Thus, this data, perhaps the richest genetic survey of any country to date, will not be fully utilized to further science.

Nature 519, 309–314 (19 March 2015) doi:10.1038/nature14230

The fine-scale genetic structure of the British population

Stephen Leslie et al.

Fine-scale genetic variation between human populations is interesting as a signature of historical demographic events and because of its potential for confounding disease studies. We use haplotype-based statistical methods to analyse genome-wide single nucleotide polymorphism (SNP) data from a carefully chosen geographically diverse sample of 2,039 individuals from the United Kingdom. This reveals a rich and detailed pattern of genetic differentiation with remarkable concordance between genetic clusters and geography. The regional genetic differentiation and differing patterns of shared ancestry with 6,209 individuals from across Europe carry clear signals of historical demographic events. We estimate the genetic contribution to southeastern England from Anglo-Saxon migrations to be under half, and identify the regions not carrying genetic material from these migrations. We suggest significant pre-Roman but post-Mesolithic movement into southeastern England from continental Europe, and show that in non-Saxon parts of the United Kingdom, there exist genetically differentiated subgroups rather than a general ‘Celtic’ population.

Link

ISBA 2014 titles

Some interesting talks and posters from the upcoming International Symposium on Biomolecular Archaeology. I don't see any abstracts on the site (yet?) but the titles are intriguing. Some that caught my eye:

• Investigating the maternal lineage diversity from an early medieval site in Southern Italy
• Ancient mitochondrial and Y chromosomal DNA reveals the western Carpathian Basin as a corridor of the Neolithic expansion
• Ancient mitochondrial DNA from the Northern fringe of the Neolithic farming expansion in Europe sheds light on the dispersion process
• The effect of demography and natural selection on pigmentation heterogeneity in late Pleistocene and early Holocene Europeans
• The genomics of equine speciation and domestication
• Ancient population genetics: new insights on horse domestication
• Species identification and analysis of the Tyrolean Iceman's clothes using next generation sequencing of ancient DNA.
• Early evidence for the use of pottery: extending the ancient lipid record to the Pleistocene.
• Whey to go – first identification of lactose in prehistoric pottery
• Use of the earliest pottery on the Western and Eastern side of the Baltic
• The geographical distribution of the Polynesian cultural complex and its association with P33-C2a1 Y chromosomes: adding data from Aotearoa (New Zealand)
• Interdisciplinary investigation of an archaic hominin femur from the Swabian Jura (South-West Germany)
• Tracing the genetic history of farming populations of El Portalón Cave in the Sierra de Atapuerca, Spain.
• Ancient human genomes suggest three ancestral populations for present-day Europeans
• Ancient DNA from Early Neolithic farmers in Europe
• Genomic diversity and admixture in Stone-Age farmer and hunter-gatherer groups in Scandinavia
• Ancient DNA reveals the complex genetic history of the New World Arctic
• A prediction of the hybridisation potential between Hominin species using mitochondrial DNA
• Population Genomics of Vikings
• Tracing the genetic profile of Sus scrofa on Romanian territory from the Neolithic period until the Middle Ages
• The origins of the Aegean palatial civilizations from a population genetic perspective
• Ancient DNA evidence for a diversified origin of ancestor of Han Chinese

Pre-Viking colonization of Faroe islands

Quaternary Science Reviews Available online 17 July 2013

The Vikings were not the first colonizers of the Faroe Islands

Mike J. Church et al.

We report on the earliest archaeological evidence from the Faroe Islands, placing human colonization in the 4th–6th centuries AD, at least 300–500 years earlier than previously demonstrated archaeologically. The evidence consists of an extensive wind-blown sand deposit containing patches of burnt peat ash of anthropogenic origin. Samples of carbonised barley grains from two of these ash patches produced 14C dates of two pre-Viking phases within the 4th–6th and late 6th–8th centuries AD. A re-evaluation is required of the nature, scale and timing of the human colonization of the Faroes and the wider North Atlantic region.

Link

Vikings and their mice

Elsewhere on the web: Viking mice conquered much of British Isles, 'Viking mouse' invasion tracked

Proceedings of the Royal Society B doi: 10.1098/rspb.2008.0958

Of mice and (Viking?) men: phylogeography of British and Irish house mice

Jeremy B. Searle et al.

Abstract

The west European subspecies of house mouse (Mus musculus domesticus) has gained much of its current widespread distribution through commensalism with humans. This means that the phylogeography of M. m. domesticus should reflect patterns of human movements. We studied restriction fragment length polymorphism (RFLP) and DNA sequence variations in mouse mitochondrial (mt) DNA throughout the British Isles (328 mice from 105 localities, including previously published data). There is a major mtDNA lineage revealed by both RFLP and sequence analyses, which is restricted to the northern and western peripheries of the British Isles, and also occurs in Norway. This distribution of the ‘Orkney’ lineage fits well with the sphere of influence of the Norwegian Vikings and was probably generated through inadvertent transport by them. To form viable populations, house mice would have required large human settlements such as the Norwegian Vikings founded. The other parts of the British Isles (essentially most of mainland Britain) are characterized by house mice with different mtDNA sequences, some of which are also found in Germany, and which probably reflect both Iron Age movements of people and mice and earlier development of large human settlements. MtDNA studies on house mice have the potential to reveal novel aspects of human history.

Link

Vikings abroad in search of women

Viking Age Triggered by Shortage of Wives?:

Sept. 17, 2008 -- During the Viking Age from the late eighth to the mid-eleventh centuries, Scandinavians tore across Europe attacking, robbing and terrorizing locals. According to a new study, the young warriors were driven to seek their fortunes to better their chances of finding wives.

The odd twist to the story, said researcher James Barrett, is that it was the selective killing of female newborns that led to a shortage of Scandinavian women in the first place, resulting later in intense competition over eligible women.

...

Soren Sindbaek, assistant professor of medieval and Renaissance archaeology at Denmark's University of Aarhus, told Discovery News that the new paper "is very right in pointing out the inadequacy" of former explanations for the Viking Age.

"We need indeed to seek for an individual, social motivation behind the fact that a large number of young men chose to set out on extremely risky voyages in hopes of acquiring wealth and esteem in foreign lands," Sindbaek said.

Ancient Viking mtDNA from Denmark

Table 1 has the data from this study, Table S3 previous Danish Iron Age and Viking results.

Related:
Iron Age, Viking Age, and Eskimo mtDNA
Ancient mtDNA from Iron Age Denmark
mtDNA of an early Danish sample

UPDATE: Frequencies of mtDNA haplogroup I several populations in Quintana-Murci et al. (pdf). The higher frequencies appear in Sindhi from Pakistan (8.7%), Kurds from western Iran and Turks from eastern and western Azerbaijan (both 5%), and Mazandarians from northern Iran (4.5%). In Russians from Oryol oblast (8.3%) (Ann. Hum. Genet. (2001), 65, 63-78). Various European groups (table).

UPDATE (June 10): From a press release related to this by the University of Copenhagen:

At the beginning of the Danish iron age, the roman legions were based as far north as the river Elbe (on the border of northern Germany) and it is thought that the man of arabian descent found in the burial grounds in Southern Zealand would have either been a slave or a soldier in the roman army. It is probable that he possessed skills or special knowledge, which the people in Bøgebjerggård or Skovgaard settlements could make use of, or he could have been the descendant of a female of arabian origin, who for reasons unknown, had crossed the river Elbe and settled down with the inhabitants of Zealand.

"This discovery is comparable to the findings of a colleague of mine, who found a person of siberian origin on the Kongemarke site," continues scientist, Linea Melchior. He was buried on consecrated ground, just as the circumstances of the arab man's burial was identical to that of the locals. The discovery of the arab man indicates that people from distant parts of the world could be and were absorbed in Danish communities.

PLoS ONE 3(5): e2214. doi:10.1371/journal.pone.0002214

Evidence of Authentic DNA from Danish Viking Age Skeletons Untouched by Humans for 1,000 Years

Linea Melchior et al.

Abstract

Background

Given the relative abundance of modern human DNA and the inherent impossibility for incontestable proof of authenticity, results obtained on ancient human DNA have often been questioned. The widely accepted rules regarding ancient DNA work mainly affect laboratory procedures, however, pre-laboratory contamination occurring during excavation and archaeological-/anthropological handling of human remains as well as rapid degradation of authentic DNA after excavation are major obstacles.

Methodology/Principal Findings

We avoided some of these obstacles by analyzing DNA from ten Viking Age subjects that at the time of sampling were untouched by humans for 1,000 years. We removed teeth from the subjects prior to handling by archaeologists and anthropologists using protective equipment. An additional tooth was removed after standard archaeological and anthropological handling. All pre-PCR work was carried out in a “clean- laboratory” dedicated solely to ancient DNA work. Mitochondrial DNA was extracted and overlapping fragments spanning the HVR-1 region as well as diagnostic sites in the coding region were PCR amplified, cloned and sequenced. Consistent results were obtained with the “unhandled” teeth and there was no indication of contamination, while the latter was the case with half of the “handled” teeth. The results allowed the unequivocal assignment of a specific haplotype to each of the subjects, all haplotypes being compatible in their character states with a phylogenetic tree drawn from present day European populations. Several of the haplotypes are either infrequent or have not been observed in modern Scandinavians. The observation of haplogroup I in the present study (<2% in modern Scandinavians) supports our previous findings of a pronounced frequency of this haplogroup in Viking and Iron Age Danes.

Conclusion

The present work provides further evidence that retrieval of ancient human DNA is a possible task provided adequate precautions are taken and well-considered sampling is applied.

Link

Geostatistics in biological anthropology of the Irish

American Journal of Physical Anthropology, Volume 136, Issue 1 , Pages 1 - 10

Geostatistics and spatial analysis in biological anthropology

John H. Relethford

Abstract A variety of methods have been used to make evolutionary inferences based on the spatial distribution of biological data, including reconstructing population history and detection of the geographic pattern of natural selection. This article provides an examination of geostatistical analysis, a method used widely in geology but which has not often been applied in biological anthropology. Geostatistical analysis begins with the examination of a variogram, a plot showing the relationship between a biological distance measure and the geographic distance between data points and which provides information on the extent and pattern of spatial correlation. The results of variogram analysis are used for interpolating values of unknown data points in order to construct a contour map, a process known as kriging. The methods of geostatistical analysis and discussion of potential problems are applied to a large data set of anthropometric measures for 197 populations in Ireland. The geostatistical analysis reveals two major sources of spatial variation. One pattern, seen for overall body and craniofacial size, shows an east-west cline most likely reflecting the combined effects of past population dispersal and settlement. The second pattern is seen for craniofacial height and shows an isolation by distance pattern reflecting rapid spatial changes in the midlands region of Ireland, perhaps attributable to the genetic impact of the Vikings. The correspondence of these results with other analyses of these data and the additional insights generated from variogram analysis and kriging illustrate the potential utility of geostatistical analysis in biological anthropology.

Link

Muslim and Christian Lebanese or Hasty Conclusions in Human Population Genetics

On my post on Genetic Palimpsests, I argued that genetic interpretations about historical events are often suspect when done with very old markers:

Often, this historical reasoning can be shaky. For example, Spencer Wells has made tall claims about the Phoenicians, the Sea Peoples, and the Carthaginians in a National Geographic article which were based on the analysis of haplogroup J and E distribution in the Levant and North Africa.

The reason for this is the following. Suppose a marker is very old, much older than the historical phenomenon under study. In the case of the above-mentioned documentary, the ages of the markers used were about 7 times greater than either the appearance of the Sea Peoples or the Carthaginians. Thus, if we observe similarity between two populations based on such old markers, we cannot conclude that they have a common recent historical origin. This is why Spencer Wells' inspired study on The Phoenicians was wrong when it claimed:

The tests could confirm that men of Tyre-Christians and Muslims alike--are related to the ancient traders. Wells and Zalloua also took samples in other parts of the Phoenician world, where results may reveal the same lineage in areas of former colonies like Sardinia and Malta.

...

During the bloody civil war of the 1970s and 1980s, some groups used the name Phoenician as an ideological weapon. Certain Maronites, the dominant Christian sect in Lebanon, claimed a direct ancestry from the Phoenicians, implying that they held a more legitimate historical claim on Lebanon than later immigrants from the Arabian Peninsula. This inflamed many Muslims. The term Phoenician had turned into a code word for Christian rather than Muslim.

...

Could genetics show that modern Lebanese, both Christians and Muslims, share the same Phoenician heritage? That's one question this project, funded by the National Geographic Society, hopes to resolve.

...

That result delights Zalloua; it supports his belief that both Muslim and Christian Lebanese populations share an ancient genetic heritage.

"Maybe now we can finally put some of our internal struggles to rest," he says.

It is clear from this article that the two possible outcomes of the study were not treated equally: the idea that Muslims and Christians are alike "delights", while the idea that they are not is demonized as contributing to sectarian violence and civil war in Lebanon.

Science should be about the facts, not about wishful thinking. The science of population genetics does have the potential to be used for political reasons, but that is no excuse for drawing unsubstantiated conclusions based on what is politically useful.

The results of the National Geographic study were never published in a peer reviewed journal, so they did not undergo the normal process of scientific scrutiny. However, it is clear why the results were not sufficient: the markers used were ancient. One cannot conclude a recent origin of two populations sharing a common ancient marker, because differences can be revealed when other, more recent, markers are used.

Indeed, in a different study (pdf) which studied more derived markers, the difference between Christian and Muslim Lebanese was made apparent:

The PC plot suggested the presence of four main groups (Fig. 3a): 1) North Africa, Figure 2 Genealogical relationships of the selected UEPs. Nomenclature as suggested by YCC (2002). 2) Near East/Arabs (including Muslim Lebanese and Ashkenazi Jews), 3) Central-East Mediterranean grouping, including Christian Lebanese and 4)West Mediterranean.

What is the reason for these conclusions? The most striking difference between the Christian and Muslim Lebanese is within haplogroup J, i.e., the haplogroup supposed to reflect their common heritage. Muslims have 56.4% of J, while Christians have 44.2%, but this is distributed 30.8%/25.6% among haplogroups J*(xJ2) and J2 in Muslims and 9.3%/34.9% among Christians. It is the high frequency of J*(x2) which indicates the substantial Arab ancestry among the Muslims compared to the Christians. So, indeed Christians appear to descend more from the pre-Arab populations of Lebanon, and presumably the Phoenicians, compared to the Muslims who are more similar to other Arabs.

The literature is full of similar hasty conclusions. The Cohen Modal Haplotype debacle is another case in point. In this case, a simple 6-locus STR haplotype in a YAP- background was taken to be indicative of Aaronic biblical ancestry, a conclusion which did not withstand further scrutiny. At present, 10 years after the Y-DNA Aaron proposition made its appearance, no evidence in support of this theory has been presented; customers of genetic testing companies dabbling in "Jewish ancestry" are expectedly at a loss.

Similarly, haplogroup R1a1 has been proposed as indicative of Viking, Slavic, Kurgan, Ukranian Paleolithic, Indo-Aryan, etc. expansions although very little is known about its phylogeny since the Upper Paleolithic.

Of course R1a1 may have hidden phylogenetic structure that could be linked to the various proposed population expansions, and Aaron's Y chromosome may have been inherited by some bearers of the CMH. But the case needs to be made.

Y chromosomes reveal limited Viking settlement in Ireland

More on this later...

European Journal of Human Genetics (advance online publication)

The scale and nature of Viking settlement in Ireland from Y-chromosome admixture analysis

Brian McEvoy et al.

Abstract

The Vikings (or Norse) played a prominent role in Irish history but, despite this, their genetic legacy in Ireland, which may provide insights into the nature and scale of their immigration, is largely unexplored. Irish surnames, some of which are thought to have Norse roots, are paternally inherited in a similar manner to Y-chromosomes. The correspondence of Scandinavian patrilineal ancestry in a cohort of Irish men bearing surnames of putative Norse origin was examined using both slow mutating unique event polymorphisms and relatively rapidly changing short tandem repeat Y-chromosome markers. Irish and Scandinavian admixture proportions were explored for both systems using six different admixture estimators, allowing a parallel investigation of the impact of method and marker type in Y-chromosome admixture analysis. Admixture proportion estimates in the putative Norse surname group were highly consistent and detected little trace of Scandinavian ancestry. In addition, there is scant evidence of Scandinavian Y-chromosome introgression in a general Irish population sample. Although conclusions are largely dependent on the accurate identification of Norse surnames, the findings are consistent with a relatively small number of Norse settlers (and descendents) migrating to Ireland during the Viking period (ca. AD 800–1200) suggesting that Norse colonial settlements might have been largely composed of indigenous Irish. This observation adds to previous genetic studies that point to a flexible Viking settlement approach across North Atlantic Europe.

Link

"Celts" in Xinjiang

PhDiva criticizes a despicable Independent article titled "A meeting of civilisations: The mystery of China's celtic mummies". As I noted in a discussion list:

There is no evidence that the Urumqi mummies spoke Celtic languages, or that they were Europeans, or even Indo-Europeans. The DNA evidence can only be used to show that they were of West Eurasian, not European origin. As for their language, none of them have been accompanied, as far as I know, by any writings. It is reasonable that they might have spoken an Indo-European language, although by no means proven.

It is a sad state of affairs that editors allow such misleading information to be published.

One of the many idiotic statements in the article:

The Loulan Beauty, for example, was claimed by the Uighurs as their symbol in song and image, although genetic testing now shows that she was in fact European.

The "Loulan Beauty" may be one of the ancestors of the Uighurs, and she certainly belongs to the archaeological heritage of the region. Thus, it is reasonable and understandable that she will be made a symbol by the current inhabitants, however tenuous the connection.

Even the Slavs of Bulgaria identify with the ancient Thracians, the Turks identify with the Hittites and other extinct Anatolians, the Arabs of Egypt identify with the Egyptians, and the modern Germanic-speaking Britons identify with the "Celts". Such sentiments are understandable, albeit naive.

What is not excusable is to excise a part of Central Asian history and claim that it belongs to Europeans, or even more absurdly to Celts. However, we should perhaps excuse the journalist for his misstep, since he lives in a country where even professional geneticists have consistently oversold their research to a credulous public ready to swallow up stories about "Viking", "Celtic", or "Pictish" origins.

mtDNA of the last Viking King

Forensic Sci Int. 2006 May 8; [Epub ahead of print]

The last Viking King: A royal maternity case solved by ancient DNA analysis.

Dissing J, Binladen J, Hansen A, Sejrsen B, Willerslev E, Lynnerup N.

The last of the Danish Viking Kings, Sven Estridsen, died in a.d. 1074 and is entombed in Roskilde Cathedral with other Danish kings and queens. Sven's mother, Estrid, is entombed in a pillar across the chancel. However, while there is no reasonable doubt about the identity of Sven, there have been doubts among historians whether the woman entombed was indeed Estrid. To shed light on this problem, we have extracted and analysed mitochondrial DNA (mtDNA) from pulp of teeth from each of the two royals. Four overlapping DNA-fragments covering about 400bp of hypervariable region 1 (HVR-1) of the D-loop were PCR amplified, cloned and a number of clones with each segment were sequenced. Also a segment containing the H/non-H specific nucleotide 7028 was sequenced. Consensus sequences were determined and D-loop results were replicated in an independent laboratory. This allowed the assignment of King Sven Estridsen to haplogroup H; Estrid's sequence differed from that of Sven at two positions in HVR-1, 16093T-->C and 16304T-->C, indicating that she belongs to subgroup H5a. Given the maternal inheritance of mtDNA, offspring will have the same mtDNA sequence as their mother with the exception of rare cases where the sequence has been altered by a germ line mutation. Therefore, the observation of two sequence differences makes it highly unlikely that the entombed woman was the mother of Sven. In addition, physical examination of the skeleton and the teeth strongly indicated that this woman was much younger (approximately 35 years) at the time of death than the 70 years history records tell. Although the entombed woman cannot be the Estrid, she may well be one of Sven's two daughters-in-law who were also called Estrid and who both became queens.

Link

Migration and evolution

Steve Sailer writes:

One promising possibility is the old chestnut question about why the personalities of today's Scandinavians don't seem all that much like their Viking ancestors. It's possible that the aggressive Viking personality was a winning hand in Darwinian terms back in the Dark Ages when other Europeans didn't have adequate defenses against Viking predations. But by the Middle Ages, Europeans had evolved the security system called feudalism and the Vikings were forced to stay home. The most aggressive then tended to slaughter each other in the kind of honor feuds described in Icelandic sagas, while the milder sorts kept their heads down, survived, and multiplied. (On the other hand, I'm rather skeptical of the notion that one group is more or less violent than another group, since humans seem to have a lot of capacity for violence. A nonviolent group probably wouldn't have survived. The obvious differences are in tendencies toward organized and disorganized violence.)

I was planning to compose a longer entry on the importance of migration in human evolution, but I don't think I will have the time to finish it (with all the morphing that I've been doing lately :) ) But, here is the gist of the idea:

Often, when we think of evolution, we think of it as being driven by differences in genetic fitness of different phenotypes, which correspond to differences in genetic fitness of individual "selfish" genes. Thus, we think of evolution if one phenotype or gene is more successful than another, and hence produces more of its copies in the next generation.

However, evolution can still occur even if all phenotypes and genes are equally successful in reproducing themselves. This is due to the fact that human populations are geographically and socially structured.

If in a given environment E, phenotype A is superior to phenotype B, then we would expect (over time) to see more of phenotype A and less of phenotype B. That is the essence of selection.

But, in the words of Epicurus "necessity is evil, but there is no reason to live under necessity".

In other words, humans -being the adaptible creatures that we are- often don't stick around in adverse environment E. Rather, quite often, the members of the disadvantaged phenotype B will find a new niche for themselves, either a new social niche, or -by migration- a new geographical one.

This type of population partition is -I believe- an important feature of human evolution, because of our enormous capacity to foresee the future and plan ahead.

Let's take Sailer's Vikings who inspired this blog entry. The Vikings stand at the middle of a long history of migrations of Germanic peoples out of northern Europe. Importantly, the people who left northern Europe (e.g., the Visigoths , the Varangians, the Vandals, etc.) represented the more active and warlike elements in the local population. They were the ones who when faced with poverty, climatic change, or population overflow, decided to find a new home by migration, war, and conquest. Consequently, modern Scandinavians are descended from the leftovers of those great movements. So, it should not come as a surprise that they are so passive, peace-loving and unlike the medieval Scandinavians who terrorized Europe.

Even earlier events in human evolution can be explained by looking at migration processes. For example, Polynesians and Ethiopians are both descended from the same African ancestors of the Upper Paleolithic. But, whereas the Ethiopians stayed close to the human cradle, the Polynesians are descended from the people who moved across Eurasia in a few thousand years and then made an almost crazy journey of colonization with primitive boats across the vast expanses of the Pacific Ocean. So, we should be willing to concede that some of the differences between the two peoples are due not only to long separate evolution, but also to the different kinds of people that would end up in the middle of the Pacific vs. the ones who would remain in the Horn of Africa.

The recent Americans are of course another classical example of the same process. European Americans differ from Europeans because they evolved (biologically and culturally) separately from their European ancestors, but they are also different because they are descended from a particular kind of European, who, being uncomfortable at home, decided to make a fresh start in the New World.

The destinations of migration processes tend to accumulate two kinds of individuals:

The adventurer type is the one who perceives opportunity and seizes it. The early Neolithic colonization, or the early American colonization is probably attributed to adventurer types.

The outcast type is the one who is uncompetitive and seeks a new homeland where competition is less fierce. The later American colonization, and probably the colonization of the ecologically extreme regions of the world was (is?) effected chiefly by outcast types.

(More later...)

Origins of Faroe Islanders

European Journal of Human Genetics (advance online publication)

Highly discrepant proportions of female and male Scandinavian and British Isles ancestry within the isolated population of the Faroe Islands

Thomas D Als et al.

Abstract

The Faroe Islands in the North Atlantic Ocean are inhabited by a small population, whose origin is thought to date back to the Viking Age. Historical, archaeological and linguistic evidence indicates that the present population of the Faroe Islands may have a mixture of Scandinavian and British Isles ancestry. In the present study we used 122 new and 19 previously published hypervariable region I sequences of the mitochondrial control region to analyse the genetic diversity of the Faroese population and compare it with other populations in the North Atlantic region. The analyses suggested that the Faroese mtDNA pool has been affected by genetic drift, and is among the most homogenous and isolated in the North Atlantic region. This will have implications for attempts to locate genes for complex disorders. To obtain estimates of Scandinavian vs British Isles ancestry proportions, we applied a frequency-based admixture approach taking private haplotypes into account by the use of phylogenetic information. While previous studies have suggested an excess of Scandinavian ancestry among the male settlers of the Faroe Islands, the current study indicates an excess of British Isles ancestry among the female settlers of the Faroe Islands. Compared to other admixed populations of the North Atlantic region, the population of the Faroe Islands appears to have the highest level of asymmetry in Scandinavian vs British Isles ancestry proportions among female and male settlers of the archipelago.

Link

Y chromosomes of Norway

This should be of interest to Norwegians and those suspecting "Viking" ancestry.



From the paper:

Haplogroup frequency distributions in the different Norwegian regions are presented (Fig. 1). The frequency of P*(xR1a) varied from 26% in the east to 45% in the south, BR*(xDE, J, N3, P) from 30% in the west to 42% in the south and R1a from 13% in the south to 32% in the middle. N3 was most frequent in the north (11%; 18.6% in the northernmost county Finnmark) and totally absent in the south. Haplogroup DE and J were rare in all regions. We observe a relatively high frequency of P*(xR1a) and R1a in the population sample from south-west and east, respectively.

Frequency of haplotypes:


Uralic admixture in the non-Saami Norwegian population:

Haplogroup N3 has been interpreted as a signature of Uralic Finno-Ugric speaking males migrating to northern Scandinavia about 4000–5000 years ago [9], [17], [35] and [60]. In the present study, N3 is observed at 4% in the overall population and at 11% in the northern region corresponding to 150,000 and 50,000 inhabitants, respectively. These numbers exceed the total number of Saami inhabitants, which is officially recognized as about 50,000 (http://www.sametinget.se). In northern Norway, the N3 percentage is 18.6% in Finnmark, 8.6% in Troms and 8.4% in Nordland (which are the three northernmost counties—Nordland being located to the south of the other two (Supplementary Data Online, Fig. 2)). There is thus a considerable pool of Saami and/or Finnish Y-chromosomes in the Norwegian population and particularly in the north.

Also of interest is the discovery of a new haplogroup:

A new haplogroup, not described earlier, was found in a single sample. Deduced from its biallelic type, it might represent a new 12f2 deletion within haplogroup P*(xR1a). The haplogroup it defines has been given the temporary name P*(xR1a)/12f2c (M. Jobling personal communication). Its haplotype composition is 15-10-17-24-10-13-14-11,14-12. There are already two known 12f2 deletions within hgJ and hgD2.

Forensic Sci Int. 2005 Dec 6; [Epub ahead of print] Links

Geographical heterogeneity of Y-chromosomal lineages in Norway.

Dupuy BM, Stenersen M, Lu TT, Olaisen B.

Y-chromosomal variation at five biallelic markers (Tat, YAP, 12f2, SRY(10831) and 92R7) and nine multiallelic short tandem repeat (STR) loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385I/II and DYS388) in a Norwegian population sample are presented. The material consists of 1766 unrelated males of Norwegian origin. The geographical distribution of the population sample reflects fairly well the population distribution around the year 1942, which is the median birth year of the index persons. Seven hundred and twenty-one different Y-STR haplotypes but 726 different lineages (Y-STRs plus biallelic markers) were encountered. We observed six known (P*(xR1a), BR(xDE, J, N3, P), R1a, N3, DE, J), and one previously undescribed haplogroup (probably a subgroup within haplogroup P*(xR1a)). Four of the haplogroups (P*(xR1a), BR(xDE, J, N3, P), R1a and N3) represented about 98% of the population sample. The analysis of population pairwise differences indicates that the Norwegian Y-chromosome distribution most closely resembles those observed in Iceland, Germany, the Netherlands and Denmark. Within Norway, geographical substructuring was observed between regions and counties. The substructuring reflects to some extent the European Y-chromosome gradients, with higher frequency of P*(xR1a) in the south-west and of R1a in the east. Heterogeneity in major founder groups, geographical isolation, severe epidemics, historical trading links and population movements may have led to population stratification and have most probably contributed to the observed regional differences in distribution of haplotypes within two of the major haplogroups.

Link

Annual Meeting of the AAPA 2006

The annual meeting of the AAPA is still months away, but the list of titles of posters and papers is available online. Here are some interesting titles:

The complex genetic landscape of Africa: a Y chromosome perspective. ELIZABETH T. WOOD, DARYN A. STOVER, VERONICA CHAMBERLAIN, CHRISTOPHER EHRET, GIOVANNI DESTRO-BISOL, MICHAEL F. HAMMER.

Whole mtDNA genome analysis of ancient African lineages. MARY K. GONDER, HOLLY M. MORTENSEN, FLOYD A. REED, ALEXANDRA DE SOUSA, SARAH A. TISHKOFF.

Mitochondrial DNA variation in Old Believer and ethnic Russian populations of northern Siberia. SAMARA RUBINSTEIN, NISHI MEHTA, MAGGIE COCCA, SERGEY ZHADANOV, L. OSIPOVA, THEODORE G. SCHURR.

MtDNA story of Turkic-speaking Altai populations: implication for the prehistory of Siberia. SERGEY I. ZHADANOV, LUDMILA P. OSIPOVA, MATT C. DULIK, MARINA GUBINA, THEODORE G. SCHURR.

Timing of the peopling of the Americas: genetic analysis early Holocene skeletal remains. BRIAN M. KEMP.

The distribution of a Native American-specific allele. KARI B. SCHROEDER, DAVID G. SMITH.

Who was buried in the Old Frankfort Cemetery? Using ancient DNA to leverage anthropometrics. CHRISTOPHER R. TILLQUIST, PETER KILLORAN, FABIAN CRESPO, MINDI KING, BRANDY SCHWALLIE, CHANDLER GATENBEE, A. HOWARD, A. HELM, DAVID POLLACK.

Variation in the upper-midface of modern ‘Hispanic’ samples compared to Caucasoid and Amerindian samples. ELIGIO J. RAMIREZ.

Fordisc 2.0 the ultimate test: What is the truth? NICOLE A. NAAR, DANA HILGENBERG, GEORGE J. ARMELAGOS.

Mitochondrial DNA variation of Yuman speaking populations. CARA R. MONROE.

Mitochondrial DNA Variation in Northern Altaian Ethnic Groups. MATTHEW C. DULIK, SERGEY I. ZHADANOV, L.P. OSIPOVA, THEODORE G. SCHURR.

Mitochondrial DNA analysis of the Jomon and Epi-Jomon individuals in Hokkaido, Japan. NOBORU ADACHI.

A study of the L1c haplogroup of the mitochondrial DNA. CHIARA BATINI, VALENTINA COIA, MAYA METNI PILKINGTON, CINZIA BATTAGGIA, JORGE ROCHA, GABRIELA SPEDINI, GIOVANNI DESTRO-BISOL, DAVID COMAS, FRANCESC CALAFELL.

Identifying the most informative regions of the mitochondrial genome using phylogenetic analysis. AMY L. NON, ANDREW KITCHEN, CONNIE J. MULLIGAN.

South American population genetic structure and history: the Y perspective. GRACIELA S. CABANA, PAUL W. LÓPEZ, ANGELA CÁCERES, BEATRIZ LIZÁRRAGA, ANNE C. STONE.

Distributions of newly defined Y-chromosome haplogroups K6 and K7 in Island Melanesia. KRISTA E. LATHAM, JONATHAN S. FRIEDLAENDER, FRANCOISE R. FRIEDLAENDER, MICHAEL F. HAMMER, TANYA M. KARAFET, GEORGE KOKI, JOESEPH G. LORENZ.

Genetic variation of Alu insertions in Easter Island supports “Slow Boats” hypothesis for the peopling of Polynesia. EMILI GONZALEZ-PEREZ, ESTHER ESTEBAN, MARC VIA, CLARA GARCIA-MORO, MIQUEL HERNANDEZ, PEDRO MORAL.

The origin of syphilis: a phylogenetic approach suggesting New World origin. KRISTIN N. HARPER.

An investigation of secular change in the craniofacial morphology of White and Black males and females in the United States. SANDRA CRIDLIN.

Ecogeographic variation in human nasal passages. TODD R. YOKLEY.

Can Khoi San cranial morphology be explained by paedomorphism? KATRIN SCHAEFER, PHILIPP GUNZ, CAROLINE FENES, PHILIPP MITTEROECKER, FRED L. BOOKSTEIN.

Are there two human ontogenies? an investigation of growth trajectories among tropical foragers and farmers. ROBERT S. WALKER.

Population structure analysis from prehistoric skeletal material. LYLE W. KONIGSBERG, JANE E. BUIKSTRA.

Serial coalescent simulations suggest weak genealogical relationships between Etruscans and modern Tuscans. ELISE M. S. BELLE, UMA RAMAKRISHNAN, JOANNA MOUNTAIN, GUIDO BARBUJANI.

Migrations across the Red Sea: Mitochondrial DNA analysis of populations from the Horn of Africa and Arabia. CONNIE J. MULLIGAN, AMY NON, ANDREW KITCHEN.

Out of Africa with admixture. ALAN R. ROGERS.

Revisiting Neanderthal mitochondrial DNA sequence variation. DAVID ILTIS.

mtDNA analysis of human remains from the Danish Iron and Viking ages. LINEA C. MELCHIOR, JØRGEN DISSING, NIELS LYNNERUP.

Prehistoric peoples and ancient migrations: Exploring population affinities in East Eurasia. KAREN P. MOODER, TIA THOMSON, FIONA J. BAMFORTH.

The genetic structure of the Aleuts and circumarctic populations and its implications for the peopling of North American. MARK ZLOJUTRO, ROHINA RUBICZ, MICHAEL H. CRAWFORD.

Historical peopling of the New World: Y chromosome roots. TATIANA M. KARAFET, STEPHEN L. ZEGURA, MICHAEL F. HAMMER.

Inferring population continuity versus replacement with aDNA: a cautionary tale in the Aleutians. SILVIA E. SMITH, M.GEOFFREY HAYES, JOAN BRENNER COLTRAIN, DENNIS H. O'ROURKE.

Anomalies of dental development in modern humans and Homo floresiensis. JOHN R. LUKACS, GREG C. NELSON, CAM WALKER.

The place of Jebel Moya in northeast African prehistory: A dental perspective. JOEL D. IRISH.

Wealth, status and gender at Bronze Age Tepe Hissar: An investigation of intracemetery variation in dental pathology prevalence in prehistoric Iran. BRIAN E. HEMPHILL.

Do early South Americans show biological similarity to Australians?: Lagoa Santa in odontometric and craniometric perspective. NORIKO SEGUCHI, HIDEYUKI UMEDA, A. RUSSELL NELSON, C. LORING BRACE.

Early human skeletal remains from Sabana de Bogotá, Colombia, South America: Implications for the settlement of the New World. WALTER NEVES, MARK HUBBE, GONZALEZ CORREAL, DANUSA MUNFORD.

Sequence variation in mtDNA hypervariable segment l indicates within haplogroup continuity between contemporary and prehistoric Aleut populations. JACQUEL L. ARISMENDI, DENNIS H. O'ROURKE.

Origins of Aleut populations: Molecular perspectives. MICHAEL H. CRAWFORD, ROHINA C. RUBICZ, MARK ZLOJUTRO.

Maternal and paternal lineages of African Americans. RICK A. KITTLES.

Genetic admixture, phenotype, and perception of admixture in Hispanics and Native Americans in New Mexico. YANN C. KLIMENTIDIS.

The phylogeography of mtDNA variation in Altaian Kazakh populations. OMER GOKCUMEN, LUDMILLA OSIPOVA, SERGEY I. ZHADANOV, O. ANDREENKOV, L. TABIKHANOVA, M. GUBINA, THEODORE G. SCHURR.

HapMap publication explosion

Haplotype map offers new insights into human disease, evolution

Cambridge, MA, Wed., Oct. 26, 2005 – In several papers published this week in Nature, Nature Genetics, PLoS Biology and Genome Research, Broad researchers and an international set of collaborators announce substantial advances in relating human genetic variation to disease and understanding human evolutionary history.

This flurry of high-profile studies are grounded in data described in a significant paper published in the Oct. 27 issue of the journal Nature by an international consortium of more than 200 researchers from Canada, China, Japan, Nigeria, the United Kingdom and the United States. In this paper, the authors describe the common patterns of genetic variation in human DNA samples collected from four sites around the world. The Consortium's findings provide overwhelming evidence for previous scientific work suggesting that genetic variants located physically close to each other are collectively inherited as groups, called haplotypes. The comprehensive catalog of all of these blocks, known as the "HapMap," which is now publicly available to the biomedical research community, has already accelerated the search for gene variants involved in common diseases and brought new insights into the genes involved in human evolution.

...

In line with the Broad Institute's commitment to building critical resources for the scientific community, HapMap data are freely available in several public databases, including the HapMap Data Coordination Center (www.hapmap.org), the NIH-funded National Center for Biotechnology Information's dbSNP (www.ncbi.nlm.nih.gov/SNP/index.html) and the JSNP Database in Japan (snp.ims.u-tokyo.ac.jp). Further information can also be found at the Broad Institute's web site (www.broad.mit.edu).

Read more:

HapMap Could Yield Genetic Clues to Many Diseases Forbes
HapMap Catalogue of Human Genetic Variation Published Bio-IT World
Phase I of HapMap complete The Scientist

Researchers have released a public database of human genetic variation, designed to help scientists study the effects of small genetic differences on health, reports an international consortium in this week's Nature. The findings suggest that only 260,000 to 470,000 single nucleotide polymorphisms (SNPs) are needed to capture all the common genetic variation in the populations studied, despite the fact that there are an estimated 10 million common SNPs in the human genome.

List of papers/editorials/commentaries (most require access):

Nature Deeper into the genome
Nature Genomics: Understanding human diversity
Nature A haplotype map of the human genome

Inherited genetic variation has a critical but as yet largely uncharacterized role in human disease. Here we report a public database of common variation in the human genome: more than one million single nucleotide polymorphisms (SNPs) for which accurate and complete genotypes have been obtained in 269 DNA samples from four populations, including ten 500-kilobase regions in which essentially all information about common DNA variation has been extracted. These data document the generality of recombination hotspots, a block-like structure of linkage disequilibrium and low haplotype diversity, leading to substantial correlations of SNPs with many of their neighbours. We show how the HapMap resource can guide the design and analysis of genetic association studies, shed light on structural variation and recombination, and identify loci that may have been subject to natural selection during human evolution.

Nature Genetics Efficiency and power in genetic association studies

We investigated selection and analysis of tag SNPs for genome-wide association studies by specifically examining the relationship between investment in genotyping and statistical power. Do pairwise or multimarker methods maximize efficiency and power? To what extent is power compromised when tags are selected from an incomplete resource such as HapMap? We addressed these questions using genotype data from the HapMap ENCODE project, association studies simulated under a realistic disease model, and empirical correction for multiple hypothesis testing. We demonstrate a haplotype-based tagging method that uniformly outperforms single-marker tests and methods for prioritization that markedly increase tagging efficiency. Examining all observed haplotypes for association, rather than just those that are proxies for known SNPs, increases power to detect rare causal alleles, at the cost of reduced power to detect common causal alleles. Power is robust to the completeness of the reference panel from which tags are selected. These findings have implications for prioritizing tag SNPs and interpreting association studies.

Genome Research
Calibrating a coalescent simulation of human genome sequence variation

Population genetic models play an important role in human genetic research, connecting empirical observations about sequence variation with hypotheses about underlying historical and biological causes. More specifically, models are used to compare empirical measures of sequence variation, linkage disequilibrium (LD), and selection to expectations under a "null" distribution. In the absence of detailed information about human demographic history, and about variation in mutation and recombination rates, simulations have of necessity used arbitrary models, usually simple ones. With the advent of large empirical data sets, it is now possible to calibrate population genetic models with genome-wide data, permitting for the first time the generation of data that are consistent with empirical data across a wide range of characteristics. We present here the first such calibrated model and show that, while still arbitrary, it successfully generates simulated data (for three populations) that closely resemble empirical data in allele frequency, linkage disequilibrium, and population differentiation. No assertion is made about the accuracy of the proposed historical and recombination model, but its ability to generate realistic data meets a long-standing need among geneticists. We anticipate that this model, for which software is publicly available, and others like it will have numerous applications in empirical studies of human genetics.

PLoS Biology The Geographic Spread of the CCR5 Δ32 HIV-Resistance Allele

The Δ32 mutation at the CCR5 locus is a well-studied example of natural selection acting in humans. The mutation is found principally in Europe and western Asia, with higher frequencies generally in the north. Homozygous carriers of the Δ32 mutation are resistant to HIV-1 infection because the mutation prevents functional expression of the CCR5 chemokine receptor normally used by HIV-1 to enter CD4+ T cells. HIV has emerged only recently, but population genetic data strongly suggest Δ32 has been under intense selection for much of its evolutionary history. To understand how selection and dispersal have interacted during the history of the Δ32 allele, we implemented a spatially explicit model of the spread of Δ32. The model includes the effects of sampling, which we show can give rise to local peaks in observed allele frequencies. In addition, we show that with modest gradients in selection intensity, the origin of the Δ32 allele may be relatively far from the current areas of highest allele frequency. The geographic distribution of the Δ32 allele is consistent with previous reports of a strong selective advantage (>10%) for Δ32 carriers and of dispersal over relatively long distances (>100 km/generation). When selection is assumed to be uniform across Europe and western Asia, we find support for a northern European origin and long-range dispersal consistent with the Viking-mediated dispersal of Δ32 proposed by G. Lucotte and G. Mercier. However, when we allow for gradients in selection intensity, we estimate the origin to be outside of northern Europe and selection intensities to be strongest in the northwest. Our results describe the evolutionary history of the Δ32 allele and establish a general methodology for studying the geographic distribution of selected alleles.

The origin of an HIV-Resistance Allele

Via John Hawks. This study is a good example of how non-uniform selection can change allele frequencies in a way that an allele may reach its highest frequency in a region different from the one where it originated. See also HIV Resistance mutation in the Bronze Age.

PLoS Biology Volume 3, Issue 11

The Geographic Spread of the CCR5 Δ32 HIV-Resistance Allele

John Novembre et al.

The Δ32 mutation at the CCR5 locus is a well-studied example of natural selection acting in humans. The mutation is found principally in Europe and western Asia, with higher frequencies generally in the north. Homozygous carriers of the Δ32 mutation are resistant to HIV-1 infection because the mutation prevents functional expression of the CCR5 chemokine receptor normally used by HIV-1 to enter CD4+ T cells. HIV has emerged only recently, but population genetic data strongly suggest Δ32 has been under intense selection for much of its evolutionary history. To understand how selection and dispersal have interacted during the history of the Δ32 allele, we implemented a spatially explicit model of the spread of Δ32. The model includes the effects of sampling, which we show can give rise to local peaks in observed allele frequencies. In addition, we show that with modest gradients in selection intensity, the origin of the Δ32 allele may be relatively far from the current areas of highest allele frequency. The geographic distribution of the Δ32 allele is consistent with previous reports of a strong selective advantage (>10%) for Δ32 carriers and of dispersal over relatively long distances (>100 km/generation). When selection is assumed to be uniform across Europe and western Asia, we find support for a northern European origin and long-range dispersal consistent with the Viking-mediated dispersal of Δ32 proposed by G. Lucotte and G. Mercier. However, when we allow for gradients in selection intensity, we estimate the origin to be outside of northern Europe and selection intensities to be strongest in the northwest. Our results describe the evolutionary history of the Δ32 allele and establish a general methodology for studying the geographic distribution of selected alleles.

Link

Ancient British mtDNA

One more paper added to the growing list of studies of ancient DNA. This time around, scientists have studied the mtDNA of Britons from the 4th to 11th century AD. The scope of the study is one of the largest I've seen so far, with 319 dental samples and 156 individuals in total. The haplogroup frequencies are shown below; the ancient sample is also split into Early and Late Saxon periods.



UPDATE

The comparative modern mtDNA were taken from the following regions. It is a bit peculiar that more continental European samples are missing, while Armenians and Palestinians are listed.

The comparative data set from modern populations of Europe for the founder and genetic distance analyses consisted of mtDNA HVS-I sequences from the following populations: Armenia (N=191), England (N=258), Estonia (N=149), northern France (N=101), Finland (N=176), Iceland (N=467), Norway (N=565), northern Germany (N=107), Palestine (N=117), Saami (N=176), Scotland (N=981), Spain (N=181) and Western Isles (N=181).

Molecular Biology and Evolution (advance access)

Tracing the Phylogeography of Human Populations in Britain Based on 4th-11th Century mtDNA Genotypes

A. Töpf et al.

Abstract

Some of the transitional periods of Britain during the first millennium AD are traditionally associated with the movement of people from continental Europe, composed largely of invading armies (e.g. the Roman, Saxon and Viking invasions). However, the extent to which these were migrations (as opposed to cultural exchange) remains controversial. We investigated the history of migration by women by amplifying mtDNA from ancient Britons who lived between approximately 300-1,000 AD, and compared these with 3,549 modern mtDNA database genotypes from England, Europe and the Middle East. The objective was to assess the dynamics of the historical population composition by comparing genotypes in a temporal context. Towards this objective we test and calibrate the use of rho-statistics to identify relationships between founder and source populations. We find evidence for shared ancestry between the earliest sites (predating Viking invasions) with modern populations across the north of Europe from Norway to Estonia, possibly reflecting common ancestors dating back to the last glacial epoch. This is in contrast with a late Saxon site in Norwich, where the genetic signature is consistent with more recent immigrations from the south, possibly as part of the Saxon invasions.

Link

Somerled's Viking roots

DNA shows Celtic hero Somerled's Viking roots

A HISTORIC Celtic hero credited with driving the Vikings out of western Scotland was actually descended from a Norseman, according to research by a leading DNA expert.

According to traditional genealogies, Somerled, who is said to have died in 1164 after ousting the Vikings from Argyll, Kintyre and the Western Isles, was descended from an ancient royal line going back to when the Scots were living in Ireland.

...

Prof Sykes’ studies of three Scottish clans have also led to the conclusion that some 500,000 people alive today are descended from Somerled - a number only bettered by Genghis Khan, who, among historical figures studied to date, has an estimated 16 million living descendants.

The MacDonald, MacDougall and MacAllister clans all claim descent from Somerled and Prof Sykes found that between 25 and 45 per cent of them shared the same Y-chromosome, of a kind normally found in Norway but rare in Scotland and Ireland.

By analysing the rate of mutation in DNA samples from clan members, Prof Sykes was able to show that the Y-chromosome came from a common ancestor who lived roughly 1,000 years ago.

He then tested five chiefs from the clans and discovered they all shared the same chromosome, which convinced him that the common ancestor must be Somerled, Lord of the Isles, in keeping with clan histories.

Abstracts from 74th Meeting of AAPA

They can be found here. Some interesting abstracts that caught my attention.

• Inter- and intraspecific variation in Pan tooth crown morphology: implications for Neandertal taxonomy. [Nenaderthals are distinct from Europeans and a separate species]
• Longevity in the Middle Paleolithic: Did modern humans live longer than Neandertals? [Increased longevity was not associated with anatomically modern humans but with the Upper Paleolithic]
• Sequence data from the autosomes and X chromosome: Evidence for ancient admixture in the history of H. sapiens? [East Asians have 2million BP polymorphism]
• MtDNA variation in North, East, and Central African populations gives clues to a possible back-migration from the Middle East. [M1 sharply differentiates North and East Africans from Sub-Saharans and may have originated outside Africa]
• Rejection of isolation by distance for human gene geography and suggested alternatives. [Human genetic diversity is structured and is not well-described by isolation by distance]
• Population structure in sub-Saharan Africans based on mitochondrial, Y chromosomal and X chromosomal DNA sequences. [Genetic diversity in Africa is explained by the fact that African populations were widely scattered and experienced gene flow between them]
• Using measures of locus-specific differentiation to find genes underlying traits subject to recent genetic adaptation: a test case using skin pigmentation. [Europeans and Asians are light due to selection on different genes]
• Demographic and selective history of African populations inferred from genome wide genetic markers. [Large multi-locus study finds significant substructure in Africa]
• The distribution of ancestral alleles among populations. [The fact that Africans have more ancestral alleles than other humans does not mean that humanity originated in Africa]
• History of modern human population structure inferred from the worldwide survey on Xp11.22 sequences. [1.1 million year old ancestry in North Africa and the Middle East]
• Demographic history of African populations inferred from mtDNA analysis. [Mankind originated in Tanzania, and Khoisan speakers originated in East Africa]

Midfacial variation in recent human, Zhoukoudian Upper Cave, and Paleoindian crania.

J.C.M. Ahern et al.

This study tests the hypothesis that the midfaces of select Late Pleistocene Asians and Paleoindians cannot be distinguished from recent Amerindians. Recent interpretations of Paleoindian remains have highlighted their variability and affinities to a variety of living non-Amerindian human populations. Although midfacial anatomy has been touched upon in some of these analyses, metric treatment of upper and lower midfacial anatomy has not been thoroughly examined. Given that midfacial anatomy is useful for determining population affinities among recent people, it may also prove effective at assessing past prehistoric population affinities.
Measurements of the upper and lower midface were collected on samples of three extant human populations: Amerindians (n=46), African Americans (n=58), and Euroamericans (n=62). Measurements were also collected on casts of the three crania from Zhoukoudian Upper Cave and the Spirit Cave and Wizards Beach Paleoindian specimens. The Upper Cave crania were chosen since they may represent a population ancestral to the first people to colonize the Americas. Spirit Cave and Wizards Beach were chosen since their differences epitomize the degree of variation and contrasting population affinities of North American Paleoindians. Using discriminant function analysis, Spirit Cave fell in the area of overlap between Amerindians and African Americans, while the other fossil crania had a higher probability Amerindian classification. Unlike some previous analyses, none of the fossil crania showed affinities with Europeans. Our results further indicate that the pattern of relationships and variation among Late Pleistocene Asians and Paleoindians was complex.

Inter- and intraspecific variation in Pan tooth crown morphology: implications for Neandertal taxonomy.


S.E. Bailey

Measures of divergence based on dental morphology are known to reflect biological distance in contemporary modern humans. Previous studies of Neandertal tooth crown morphology have shown that they possess a pattern of trait frequencies that differs significantly from that of contemporary and fossil anatomically modern humans. However, there is no taxonomic ‘yard stick’ against which to interpret the degree of dental divergence observed. The goal of this study was to test whether the dental morphological differences between Neandertals and anatomically modern humans were typical of subspecific (Pan troglodytes troglodytes:Pan troglodytes schweinfurthi) or closely related specific (Pan troglodytes:Pan paniscus) taxa. Eighteen dental crown traits were used to assess inter- and intraspecific variation. A Mean Measure of Divergence statistic was used to calculate morphological distance. The hominin sample included 33 Neandertals, 7 early modern humans, 19 Upper Paleolithic Europeans, and 179 contemporary humans from seven geographic regions. The Pan sample included 37 P.t. troglodytes, 44 P.t. schweinfurthi and 33 P. paniscus specimens. Measures of divergence based on pair-wise comparisons of Neandertals and anatomically modern humans were found to be higher than those derived from both subspecific and specific pair-wise comparisons of Pan. Moreover, Neandertals show no morphological affinity to either Upper Paleolithic or contemporary Europeans and are more than twice as divergent from all contemporary human samples as these samples are from each other. In as much as Pan represents an appropriate model for interpreting dental morphological divergence in Homo, these results are broadly supportive of the specific status of Neandertals.

Natural selection in the Tibet Autonomous Region.

C.M. Beall et al.

Indigenous high-altitude populations have been exposed to the opportunity for natural selection. The ability detect natural has been hampered because the genetic bases of the quantitative traits that appear to be adaptive are often unknown. However, Tibetan populations have a major gene for oxygen saturation of hemoglobin. One allele at the inferred locus is associated with 6-10% higher levels and less hypoxemia. We reported that Tibetan women residing at 4000m altitude with a high likelihood of having one or two alleles for high oxygen saturation had more living children because fewer of their live births died during infancy. Those findings suggested that high-altitude hypoxia is acting as an agent of natural selection on the locus for oxygen saturation of hemoglobin. Here, we consider the implications for understanding the evolution of adaptations to the environment. The relative fitness of the low saturation genotype as compared with the two high saturation genotypes was 0.44 based on the ratio of the number of living children. This relative fitness was lower than reported for comparisons of Hb AA and AS genotypes in malarial areas (0.66 – 0.88). Hypoxic stress differs qualitatively from malaria stress: hypoxia is constant whereas malaria parasitemia level fluctuates. Thus, the selective advantage of the high saturation allele is probably constant whereas the selective advantage of an antimalarial genotype may be intermittent. Large fitness differences among genotypes indicate the potential for rapid change in allele frequency. Human genetic adaptation may be rapid and may depend upon the nature of the environmental stress.

MtDNA diversity in six West Indian Islands throughout the Anglophone Caribbean.

J. Benn Torres et al.

The Caribbean is an example of a convergence of people and cultures from several continents. Few researchers have investigated how this phenomenon affected immigrants and their subsequent communities, even fewer have attempted to examine this convergence using anthropological genetics. In this analysis, mtDNA hypervariable region I (HVI) and haplogroup diagnostic RFLPs are examined in 318 individuals from six Afro-Caribbean communities in Dominica, St. Lucia, St. Kitts, St. Vincent, Grenada, and Trinidad. Genetic diversity and maternal genetic contributions to contemporary Caribbean populations are examined and comparisons are made between these data and those published from other African and African-derived populations.

All samples were collected from buccal swabs, extracted, and amplified using standard methods. The HVI was sequenced and 14 RFLPs were typed to determine the haplogroup. The Caribbean sequence summary statistics (pi, theta, gene diversity, average number of nucleotide differences, and Tajima’s D) are all similar to each other and similar to published African data. MtDNA haplogroup L is detected in 93% of the total sample, while the remaining 7% consists of haplogroups A, C, F, J, N1c, U6, and U7. The presence of non-L types is indicative of non- Sub-Saharan African female gene flow into these communities and for the most part, is likely due to recent immigration. Different ethnic groups make up the African Diaspora, such as African-Americans, West Indians/Afro-Caribbeans, and Afro-Latinos, this study examines the origins of a little studied group within this Diaspora.

Searching for signatures of natural selection in high altitude populations.

A.W. Bigham et al.

Hypoxia, caused by lowered barometric pressure at high altitude (defined as >2500 m above sea level), results in severe physiological stress to the human body. Although the suite of human physiological responses to this environmental condition has been well documented, the genetic bases for these adaptations remain unknown. To search for genes possibly involved in adaptation to high altitude, we used FST and other measures of allele frequency differentiation. Local natural selection especially positive selection can lead to elevated allele frequency differences measured as high FST and locus specific branch length (LSBL). Although demographic factors as well as genetic drift can also affect differences between populations, identifying high LSBL and high FST on genome-wide SNP datasets can be a powerful tool to rank candidate genes. Next, by comparing a high altitude, Indigenous American population (Quechua) to a low altitude, Indigenous American population (Nahua) using these statistics, a list of 451 SNPs (threshold FST >0.20) and 636 genes within 40kb region of those markers was generated. Based on this dataset, candidate genes that may have undergone natural selection in the Quechua population were revealed. Among these are nitric oxide synthase 2A (NOS2A) and endothelin 1 (Edn1).

Body orientations, sleep positions, and breast feeding behavior amongst solitary and co-sleeping (bedsharing) human mother-infant pairs: mutual physiological regulatory effects.


T. Brown et al.

Since the “back-to-sleep” campaign initiated in 1992, the rate per 1000 live births of American infants dying from SIDS has been reduced by half. This NIH funded research provides a basis for further appreciating how the mother’s body and responses in addition to the infant sleeping on its back can create an adaptive “micro-environment” for the human infant, and how both the mother and infant, by virtue of their sensory interactions, changes each other’s physiological status. 15 routinely solitary sleeping breastfeeding infants and their mothers and 23 routinely bed sharing breastfeeding mother-baby pairs sleeping apart and together over three consecutive nights were filmed using infrared cameras. Data collected on body orientation, sleep position, crying, breastfeeding, and maternal responses, as mothers and infants shift between bedsharing and separate room sleeping reveal changes in maternal-infant interactions involving partner-induced arousal patterns and overall sleep duration. Breastfeeding doubled when mother and their infants slept together, and infants cried significantly less. Decreased infant crying may be related to the shortened temporal latencies between when the infant aroused and when their bedsharing mothers responded. This makes problematic a 1999 recommendation by the American Consumer Product Safety Commission, to “never sleep with a baby.”

Ethnic and biological identity in New Kingdom Nubia.

M.R. Buzon

The populations of Nubia and Egypt have had a long history of interaction. While past studies have often focused on the unidirectional changed forced on Nubia by Egypt, more recent paradigms emphasizing the dynamic and bidirectional nature of these power relations are more appropriate for this situation. The events that occurred around the time of the Egyptian New Kingdom occupation of Nubia are significant. It is during this time that the foundations of the Nubian Napatan Kingdom, which ruled Egypt as the 25th Dynasty, were being built. Scholars disagree about who controlled Nubia during this important time: Egyptian colonists or native leaders. In this paper, these issues are addressed using a bioarchaeological approach.

The people buried using Egyptian and Nubian ritual at the New Kingdom site of Tombos, located at the third cataract of the Nile in Nubia, are the focus of this research (N=100). In addition, 1,287 individuals from contemporaneous Egyptian and Nubian sites are examined in order to comparatively assess the Tombos population. Multivariate statistical analyses of cranial measurements and cranial non-metric traits are used to evaluate the genetic relationships between Tombos and these comparative populations. The analyses of genetic affinities suggest that the cranial morphology of the Tombos population is more heterogeneous than that of the Egyptian populations. This heterogeneity, however, is also characteristic of the native Nubian populations. Combined with the mixed ethnicity portrayed through archaeological indications of burial ritual, it is apparent that Tombos was comprised of an ethnically and biologically mixed group of people.

Artificial cranial deformation in the prehistoric lower Mississippi river valley.

S.N. Byers

A study was performed on the cranial deformation found among prehistoric individuals from Louisiana. The type, degree, and characteristics of the deformation are presented. In addition, hypotheses are tested concerning the association between presence or degree of cranial deformation and social/biological groups: warriors vs. non-warriors, elites vs. commoners, priests vs. commoners, male vs. female, and all members of society. Testing protocols are generated for each hypothesis and the fit between the data and the protocols tested. The results of these tests indicate that cranial deformation is not more common in some groups than in all members of society, indicating that the practice was not limited to groups such as warriors, elite, priests, or even only one of the sexes. The major finding is that this cultural practice appeared to increase in frequency through time from the oldest to the youngest site.

A reassessment of human cranial metric and nonmetric trait heritabilities.

E.A. Carson

Quantitative genetics models of human populations often rely on trait heritability rates to represent the genetic variability of phenotype. The heritability ‘gold standard’ was established 20 years ago by Sjøvold (1984) and Devor (1987), whose estimates of genetic inheritance for craniometric and, in Sjøvold’s case, cranial nonmetric traits are universally used and often averaged to obtain an overall heritability rate for population genetics models. Each of these studies, however, is problematic. The heritabilities reported by Sjøvold were calculated using linear regression, a technique which makes assumptions regarding the variance matrices and parental-offspring environmental correlation that are not valid for humans. In addition, measures typically included in anthropological studies such as nasal breadth, maximum cranial length and breadth, were not assessed in Sjøvold’s study. While Devor (1987) did report heritabilities for these established cranial dimensions, his data were collected on living humans; the use of soft tissue measurements as a proxy for skeletal dimensions has since been called into question.

The current study addresses each of these problems by utilizing maximum likelihood variance component analysis to calculate heritability estimates from a sample of 200 parental-offspring pairs of crania from the Hallstatt, Austria ossuary, the same skeletal population assessed by Sjøvold. Metric data were collected on 58 standard cranial landmarks using a Microscribe 3-D digitizer that allow for the calculation of 36 linear cranial measurements commonly used by physical anthropologists (Howells, 1989). This poster presents updated heritability estimates for these measures, as well as for 36 standard cranial non-metric traits.

Longevity in the Middle Paleolithic: Did modern humans live longer than Neandertals?

R. Caspari

Increased longevity, expressed as the number of individuals surviving to older adulthood, represents one of the ways that Upper Paleolithic Europeans differ from earlier European populations. It remains unclear whether this increase in adult survivorship is an attribute of the Upper Paleolithic itself, or whether it occurred in earlier anatomically modern humans migrating into Europe from elsewhere. In this paper we address this issue by comparing anatomically modern humans associated with the Middle Paleolithic of Western Asia to their Upper Paleolithic counterparts.

We examined differences in longevity by assessing the ratio of older to younger adults (OY ratios) in two earlier penecontemporary dental samples, both associated with the Middle Paleolithic: Neandertals and fossils considered anatomically modern Homo sapiens from Western Asia. Younger and older adult status was assessed by M3 eruption and wear seriation of each sample: M3 eruption indicated adulthood, and older adulthood was defined as the age at which individuals could first potentially become a grandparent (double the age of M3 eruption). Significance of the difference in ratios between the groups was tested using distributions generated by random resampling with replacement. Our results do not reject the null hypothesis of no difference between the two Middle Paleolithic populations. We conclude that the dramatic increase in adult survivorship was not a hallmark of the earliest modern humans, but instead occurred more recently coinciding with the Upper Paleolithic. Whether or not modern humans and Neandertals were conspecifics, this suggests that the increase in adult survivorship associated with the Upper Paleolithic was not directly linked to speciation.

The truth is out there: how NOT to use FORDISC.

D. Freid

FORDISC is an interactive computer program designed to classify an unknown adult cranium based on the reference samples in its database. FORDISC uses discriminant functions to construct a classification matrix and assign group membership of the unknown cranium into one of the selected reference groups. The researcher guides the analysis by choosing the populations against which to classify the unknown, choosing from eleven population samples from the Forensic Anthropology Data Bank or twenty-eight population samples from Howells’ (1989) worldwide database. The utility and efficacy of FORDISC has been criticized for providing ‘incorrect’ classifications, however these disputed results are often due to inappropriate reference samples and failure to properly evaluate the typicality and posterior probabilities provided by the program. In this paper, unknown crania from populations known not to belong to any of the reference samples will be analyzed, demonstrating the interpretation of posterior and typicality probabilities provided in the FORDISC output and the importance of the use of an appropriate reference sample.

An application of ancient DNA analysis to an early Byzantine monastic community.

A.M. French et al.

The degree of contact among ancient populations and the extent of human historical movement have long been topics of interest and debate. While archaeological, linguistic, and textual evidence provide much information on historical patterns of migration, the record is often incomplete. A combination of biological and historical data and the introduction of methods such as ancient DNA analysis provide a more complete picture of historical migration patterns. Populations from the early Byzantine period (5th – 7th c. C.E.), when cultural and probably biological interaction among peoples of different geographic regions was common, are especially appropriate for such an analysis. An examination of genetic material from adult and subadult remains at St. Stephen’s, a Byzantine monastery in Jerusalem, has proven particularly useful in revealing some patterns of migration during the Byzantine period.

In this study, levels of genetic heterogeneity of mitochondrial DNA both within and between the subadult and adult populations at St. Stephen’s are examined to determine the likelihood that the individuals were members of the same genetic population. As many of the subadults are too young to be pilgrims they are, most likely, representative of the local region. Additionally, the sequences from the St. Stephen’s collection are compared with genetic data from worldwide populations in order to determine the most likely place(s) of origin for members of the St. Stephen’s assemblage. The genetic data, in conjunction with textual and archaeological evidence, illuminates some patterns of population movement during the Early Byzantine era into Jerusalem, especially those associated with ecclesiastical institutions.

A measure of biological distance in Nubians: a look at intrapopulation variation.

K. Godde. California State University, Sacramento.

Biological distance studies typically measure the genetic distance between populations. However, little has been done to assess the distance within specific populations. This study looked at six subpopulations of Nubians separated geographically and/or temporally to determine if variability within populations was statistically significant. In order to measure this, twenty nonmetric traits were observed on a total of 319 skulls, representing three temporally distinct periods from Semna South, including the Meroitic, X-Group, and Christian eras. Tsuneko Hanihara provided data on 180 additional crania (personal communication) from three other Nubian subpopulations that were spatially and temporally distinct from the other groups. These data were from the sites of Kerma (12th –13th dynasty), Sesebi (recent population), and the islands of Hesa and Biga (pre-Christian). All six subpopulations were compared to one another using Mean Measure of Divergence (MMD), its variance, standard deviation and the standardized MMD. The results of the statistical analysis showed that there was little variability between most of the samples. However, the MMD results of the Meroitics and Hesa and Biga were only .01 away from being statistically significant at the .05 level. Additionally, the difference between Kerma and the Meroitics was statistically significant at the .05 level. These samples were not separated by the greatest amount of geographic or temporal distance, and thus these explanations cannot completely account for the difference. In light of this study, further analysis should address whether it is necessary to separate highly variable subpopulations when attempting to measure biological distance on a global scale.

Variation in the juvenile craniofacial form: a pilot study.

R.A. Gonzalez

Much research has been conducted in the area of age determination of juvenile skeletal remains for biological profiling purposes within a medico-legal context. However, the ability to determine sex and group affiliation from juvenile skeletons is limited and often unreliable (Kerley, 1976). In fact, identifying sex and group specific differences with any degree of reliability is one of the major problems in the analysis of juvenile skeletal remains (Scheuer and Black, 2000).

This pilot study presents initial findings of human variation as expressed in the juvenile craniofacial form. A sample of 28 groups divided according to age, sex, and group affiliation was studied utilizing 22 common cephalometric measurements of American children of African and European descent. A glm manova procedure and principal component analysis served to test for the presence of sex and group specific features in the juvenile craniofacial skeleton throughout development.

The findings of this initial investigation demonstrate a statistically meaningful sex and group specific pattern of size and shape differences throughout development. Additionally, this study suggests that for each age group category utilized in the analysis, ages 6-12, it is possible to clearly identify the sex and group affiliation of juvenile skeletal remains for forensic biological profiling purposes. If the preliminary results are correct, then this investigation provides evidence of morphological differences that can be accurately identified throughout craniofacial development. These findings provide the basis for future research in which this investigator will use to develop biological profiling standards for juvenile skeletal remains.

Sequence data from the autosomes and X chromosome: Evidence for ancient admixture in the history of H. sapiens?

M.F. Hammer et al.

A longstanding question in anthropology asks whether the history of our species is characterized by an expansion from an isolated panmictic population with complete replacement of archaic forms, or by admixture among divergent allotaxa. While mtDNA data support a recent and complete replacement model, nuclear loci present a more complicated picture. Two major problems associated with interpreting the heterogeneous patterns of variation observed at multiple nuclear loci are that sampling procedures vary across studies, and experimental designs generally lack statistical power to detect archaic admixture. We are undertaking a systematic survey of DNA sequence variation at 90 unlinked nuclear loci and developing a statistical framework (to be presented by Jeff Wall) to explicitly test the hypothesis of no admixture between modern and archaic forms, and for estimating the admixture ratio (if the null hypothesis is rejected). Our approach involves sequencing three windows of ~2 kb spanning ~16 kb at each locus in a panel of 90 individuals from 6 populations. Preliminary data from two loci that show evidence of ancient admixture will be discussed. A gene tree constructed from sequence data at the first locus roots in East Asia and has a most recent common ancestor ~2 million YBP. The pattern of nucleotide variation at the second locus reveals two major lineages that have not undergone recombination for over 2 million years, and statistically rejects the null hypothesis of panmixia during the early ancestry of modern humans.

MtDNA variation in North, East, and Central African populations gives clues to a possible back-migration from the Middle East.


A.D. Holden et al.

The general timeline for human occupation of Africa has been studied extensively. However, questions involving Upper Palaeolithic migrations still persist. One remaining question is the presence of the mitochondrial M1 haplogroup in North and East Africa. Some (Quintana-Murci et al. 2004, 1999) argue that the presence of M1 in modern Africans is a remnant of the original M haplogroup that left Africa 60 kya via the Horn of Africa. Others (Forster, 2004) propose that it is instead the result of a back-migration from the Arabian Peninsula from 20 kya. This research aims to test these two competing hypotheses.

We analysed mtDNA variation in ~250 persons from Libya, Somalia, and Congo/Zambia, as representatives of the three regions of interest. Our initial results indicate a sharp cline in M1 frequencies that generally does not extend into sub-Saharan Africa. While our North and especially East African samples contained frequencies of M1 over 20%, our sub-Saharan samples consisted almost entirely of the L1 or L2 haplogroups only. In addition, there existed a significant amount of homogeneity within the M1 haplogroup.

This sharp cline indicates a history of little admixture between these regions. This could imply a more recent ancestry for M1 in Africa, as older lineages are more diverse and widespread by nature, and may be an indication of a back-migration into Africa from the Middle East. Further research on this topic includes more extensive population samples from the Middle East, as well as possible correlations of M1 to the Afro-Asiatic language family.

Rejection of isolation by distance for human gene geography and suggested alternatives.


K. Hunley et al.

Isolation by distance population structure is tested for the worldwide pattern of human genetic diversity using a large short tandem repeat (STR) data set (Cann et al., 2002, Science, 298: 261-2). A subset of 27 populations, chosen on the basis sample size, was analyzed. Each individual was represented by 377 autosomal short tandem repeat (STR) genotypes. Malecot’s genetic kinship was calculated between population pairs. Scatterplots and regression methods were applied analyze the relationship between genetic kinship and geographic distance.

All African/non-African population pairs show about the same degree of genetic kinship, regardless of geographic distance. European/non-European comparisons show two strata of genetic kinship. The first stratum presents European/African pairs, while the second stratum contains European/Asian and European/Native American pairs. There is no trend for genetic kinship to decrease with increasing geographic distance. Finally, comparisons between Asian with non-Asian samples reveal three strata, the first stratum includes Asian/African pairs, the second stratum includes Asian/European pairs, and the third stratum includes Asian/Native American pairs. The pattern is remarkable. Rather than isolation by distance, it reflects a pattern of nested subsets. Non-Africans possess a subset of the variation in Africans; Asians and Native Americans possess a subset of the variation in Non-Africans; and Native Americans possess a subset of the variation in Asians. The nested subset pattern of genetic diversity is consistent with a model that postulates a succession of ancient founder events that occurred as the human species expanded its range and occupied new continents.

The relationship between a quantitative measure of facial harmony and subjective measures of facial attractiveness.

P.L. Jamison et al.

The craniofacial variability index (CVI) summarizes the variation in Z-scores across a set of sixteen common craniofacial measurements and can be used as a measure of facial harmony. Previously we have shown that high values of this summary statistic correlate strongly with individuals known to have congenital craniofacial syndromes. In the present study we hypothesized that low values of this measure correlate with attractive or harmonious faces. The CVI was calculated for 205 adult females who had previously been ranked for attractiveness using a panel of male and female judges. The judges used a seven point Likert scale to rate each subject from above average in appearance to below average in appearance. Mean ranking scores for each subject were then used to create three groups, above average (n-34), average (n=145), and below average (n=21). ANOVA demonstrated significant differences in CVI scores of the three groups and Bonferroni post hoc tests revealed that the subjects in the “above average” group had significantly lower CVI scores than the subjects in the other two groups. Mean CVI did not differ significantly between the average and below average groups. These results indicate that the CVI is an effective measure of facial harmony and suggest that it may be a useful tool in testing some of the hypotheses that have been put forward regarding physical attractiveness and reproductive fitness.

Environmental variability, life history tactics, and the Neanderthal extinction.

J.H. Jones

In this paper, I use the demographic theory for structured populations in variable environments to shed light on the demise of the Neanderthals. Humans are – and probably most hominins were – characterized by highly structured life cycles. That is, age-specific schedules of reproductive investment are far from constant across the life cycle. In the presence of environmental variability, this structure induces correlations in vital rates across environments that can fundamentally alter optimal life history tactics. I present stochastic models of human population dynamics in a variety of stochastic environments showing that, in general, increased variability favors (1) delayed age at maturity and (2) long reproductive span. Recent histological analyses of Neanderthal teeth suggest their age at maturity was significantly earlier than that of anatomically modern humans. I show that under a reasonable range of demographic schedules, this early age at maturity would have increased the probability of extinction of Neanderthal populations under the right environmental conditions. Drawing upon Pleistocene temperature proxy data from the Greenland Ice Core Project, I show that high-frequency fluctuations increased significantly in the period more or less coincident with the disappearance of Neanderthals, consistent with this hypothesis. These results suggest the possibility that Neanderthal extinction was driven by intrinsic features of their biology and not through competition with anatomically modern humans.

Population expansions in South Indian caste and tribal populations: inferences from genetic data.


L.B. Jorde et al.

The origins and affinities of Hindu caste populations remain poorly understood. To investigate the relationships between Hindu caste populations, Indian tribal populations, and other populations, we have genotyped 45 short tandem repeat polymorphisms (STRPs) in 151 members of tribal populations and 437 members of caste populations from South India. These same STRPs have also been assayed in 142 Africans, 117 Europeans, and 61 East Asians. STRP heterozygosity was quite similar among all caste populations, with an average of 69%. The average heterozygosity among tribal groups was somewhat lower (66%), and it varied considerably among populations, with a range of 54% to 74%. The Fst value for the caste populations was relatively small (0.9), but the Fst value for the tribal populations (4.8%) was slightly higher than for our collection of sub-Saharan African populations (3.7%). Genetic distance analyses show that the caste and tribal populations occupy a position intermediate between E. Asian and European populations, as expected. In marked contrast to the caste populations, several of the tribal populations (Yanadi, Kattuniaken, Paniyan, and Chenchu) are extreme outliers on a neighbor-joining tree. These results are all highly similar using either STRPs or Alu insertion polymorphisms, and they are consistent with a much higher rate of genetic drift in the tribal populations than in caste populations. The matrix coalescent approach was applied to these data to estimate population growth parameters in caste vs. tribal populations, and these results will be discussed.

Mitochondrial DNA variation among populations of Mesoamerica and the American Southwest: Does Uto-Aztecan represent a biological unit?

B.M. Kemp et al.

Anthropologists have long noted the archaeological, cultural, and linguistic parallels between indigenous populations residing in Mesoamerica and the American Southwest. The most notable ties are the northward spread of agriculture from central Mexico into the Southwest and the presence of Uto-Aztecan speaking populations in both regions. Thus, it has been suggested that proto-Uto-Aztecan speakers were responsible for the spread of agriculture, possibly taking the form of a northward human migration. If true, Uto-Aztecan speakers from both areas should be more genetically related than they are to non-Uto-Aztecan speaking populations, regardless of geographic location.

This hypothesis was evaluated by assigning the mtDNA of over 900 individuals from fourteen extant populations (Uto-Aztecan and non-Uto-Aztecan from the Southwest and Mesoamerica) and one pre-Columbian population (Aztecs from Tlatelolco, Mexico) to one of the five Native American haplogroups: A, B, C, D, or X. These data exhibit a pattern of regional continuity and, therefore, substantial difference between regions. Additionally, the haplotypes (from the sequence of hypervariable regions I, II, and III) of over 700 of these individuals were identified. Analyses of these data demonstrate that very few maternal lineages are shared between populations and network analyses demonstrate that the majority of clades are geographic, not linguistic. The patterning of mtDNA variation suggests these regional genetic differences are of great antiquity and opposes an accompanying human migration with the spread of agriculture. We, however, point out alternative possibilities not covered by our investigation, but that are currently being tested by other colleagues.

Comparison of genetic and linguistic phylogenetic reconstructions as a means of investigating the evolution of the Semitic language family.

A. Kitchen et al.

Inference of the history of the Semitic language family has long been controversial. In order to address this problem, we have taken an interdisciplinary approach in which genetic and linguistic evolutionary relationships are compared through independent phylogenetic reconstructions of genetic and lexical data.

Our phylogenetic analyses of genetic data (mitochondrial control region DNA sequence from three Semitic-speaking populations) demonstrates that Ethiopic Semitic populations are basal relative to non-African Semitic-speakers. While greater antiquity of African populations relative to non-Africans is not surprising, genetic diversity has never been explicitly compared between African and non-African Semitic-speakers. This result suggests that if Ethiopian Semitic did originate in Arabia, it may have been introduced to Ethiopia in the absence of significant gene flow from a less diverse and evolutionary younger non-African population.

Concurrent analysis of lexical data (Bender’s modification of Swadesh’ 100-word lists for 15 Ethio-Semitic populations) using phylogenetic techniques borrowed from evolutionary systematics allows us to contrast population history, gene-flow and linguistic evolution within Semitic populations. Applying maximum parsimony and distance phylogenetic reconstruction methods to our lexical dataset, and comparing the resulting lexical and genetic phylogenies, we test alternative hypotheses of Ethio-Semitic language evolution. Our results largely support Bender's original classificatory scheme of Ethio-Semitic languages. Comparative analyses of genetic and linguistic phylogenetic reconstructions of Semitic-speaking populations should help resolve questions concerning the genetic and geographic origin of the language family.

Polygenotype-environment interaction and the Boas immigrant data.

L.W. Konigsberg et al.

The Boas immigrant dataset has recently seen a resurgence of interest, with a number of studies published using methods not available to Boas in the pre-computer era. These analyses have tended to take alternative views on the importance of polygenotypic effects as versus environmental plasticity. In this paper we re-analyze the Boas dataset with an eye to characterizing the effect of polygenotype-environment interaction on the cephalic index.

We use data on 13,732 individuals taken from Clarence Gravlee’s website (http://lance.qualquant.net/boas/data.htm). Treating the data as composed of many unrelated families and controlling for age at measurement and immigration status we estimate a narrow sense heritability for the cephalic index of about 0.74. This figure is an overestimate because it does not account for the different familial ancestries. Allowing for the original seven groups defined in Boas’s study, the within-group heritabilities are substantially lower with none reaching above 0.60. This analysis shows that we cannot ignore the existence of group-structure in the Boas data, for to do so causes cephalic index to look “more genetic” (because of increasing the genetic variation around a grand mean). Neither can we ignore the effect of the environment, for as Boas and subsequent studies (as well as this one) amply demonstrate, groups’ cephalic indexes are subject to differential responses following immigration to the United States. Consequently, the Boas data do not tell us whether cephalic index is about genes versus environment, but rather that the index is about genes and the environment.

Grandma’s right: A sleeping baby may be a growing baby.

M. Lampl

The irregularity of infant sleeping behavior is a significant biocultural issue, with much advice-seeking and offering with little scientific basis. This study aimed to investigate whether infant sleep patterns were a biobehavioral indicator of growth. Three independent statistical methods were used to test the hypothesis that the irregular increases and decreases in infant sleeping behaviors were related to episodic (saltatory) spurts in infant body length growth. Detailed daily diaries recorded the continuous patterns of sleep for twenty-four infants (15 females, 9 males) during the first year of life for durations of 4 to 12 months (n= 5660 daily records). Total daily hours of sleep and number of episodes were the variables studied. A pulse detection algorithm (CLUSTER) clarified that infant sleep irregularity consisted of sleeping peaks and troughs for all infants with an average of 4.7 more hours and/or 3 more naps per day for two days during peaks. These patterns were compared to previously identified growth spurts in body length by coincident analysis. Significant nonrandom copulsatility was identified between the two independently collected data sets (physical growth and sleep patterns) suggesting that daily sleeping behavior and growth in infant body length are a coupled biological process. Maximum likelihood logistic regression models quantified a 25% increased likelihood of a growth spurt for each hour the infants slept above their non-growth interval sleeping averages.

These data link behavioral state changes and the biological mechanisms underlying the timing and control of human growth spurts, adding growth biology to the enigmatic question of “why do we sleep?”

Changes in sexual dimorphism in Europeans in the last 30,000 years.

S.-H. Lee ET AL.

In Europe, sexual dimorphism decreased from the Upper Paleolithic through the Mesolithic followed by a slight increase from the Mesolithic to the Neolithic. In all, the level of sexual dimorphism typical of recent Europeans was reached by the end of the Neolithic. Earlier work (Frayer, 1980) documented these trends by plotting means in sexual dimorphism in dental, cranial and postcranial metrics for the three periods, attributing the reduction trend to greater gracilization in males from the Upper Paleolithic to the Mesolithic. The subsequent increase in sexual dimorphism was a result of stabilization of the male trend, coupled with a decrease in female metrics from the Mesolithic to the Neolithic.

The previous study was conducted by pooling data into three time periods and testing for differences across these divisions. In this study, the pattern of gracilization over time was examined by tracking male and female metrics separately through the entire time span. Here, we treat the time period as a continuous sample and use an updated data set to address two questions: 1) the pattern of change in sexual dimorphism; and 2) the contribution of changes in each sex over time to the observed pattern of variation. We apply a data re-sampling approach and ask if changes occurred gradually through the 30,000 year time span. Our results confirm earlier work, but deepen the understanding of the temporal patterning of trends of sexual dimorphism in post-Neandertal European populations.

Predictions of isolation by distance and alternatives for human gene geography.

J.C. Long et al.

Many human genetic examples of correlations between genetic and geographic distances are attributed to isolation by distance, meaning a population structure where the reproductive dispersal of individuals is restricted relative to the range of the entire population. Wright, Malecot, Kimura, and Slatkin have developed the rigorous genetic theory of isolation by distance. While each architect of the theory has developed a slightly different version, the common result is that at equilibrium there is a titration between genetic differentiation and the geographic distance between localities. Isolation by distance implies for the human data that genetic drift and local dispersal have shaped the genetic structure of our species.

Alternatively, other mechanisms such as a step-wise range expansion can create a correlation between genetic and geographic distance. In this circumstance, the correlation between genetic and geographic distance does not reflect local dispersal. Rather, it reproduces the migration paths and succession of founder events that occurred during the process of range expansion.

The purpose of this paper is to show how hierarchical F-statistics can distinguish between these two alternative population structures. Computer simulations are used to illustrate the approach and potential outcomes. We use these simulations to determine the number of genetic loci that must be assayed in order to reliably distinguish patterns of genetic divergence. In addition, we explore the effect of systematic sampling biases such as sampling clusters of widely dispersed populations on the outcome of analyses.

Analysis of mtDNA haplogroup monomorphism in a sample of a Native American population combining modern and ancient DNA research.


E. Marchani et al.

We observe a lack of mitochondrial haplogroup variation not only among modern Eastern Inuit, but also among their ancestors, the Thule. Both groups possess haplogroup A exclusively, in contrast to other Native American groups, who possess some combination of haplogroups A, B, C, D, and X.

This lack of variation might have been caused by genetic drift, given a recent history of small effective population size. This hypothesis seems plausible, given archaeological evidence that the Thule expanded rapidly across the far north approximately 1000 years ago from a relatively small founding population. Here, we ask what hypotheses about population history can be excluded on the basis of the observed absence of mitochondrial haplogroup variation.

We test hypotheses about population history using coalescent simulations. We are able to exclude hypotheses of a bottleneck in the distant past, while we are not able to reject hypotheses of a bottleneck within the recent past. Our results both describe and help to explain the demographic and biological processes that result in the unique phenomenon of mitochondrial haplogroup monomorphism.

Population structure in sub-Saharan Africans based on mitochondrial, Y chromosomal and X chromosomal DNA sequences.

M. Metni Pilkington et al.

Africans harbor the greatest genetic diversity, the deepest TMRCA estimates, and the largest effective population size of humans. Here we ask whether the large effective population size is associated with a highly structured population and how population structure compares across loci. We address these questions using DNA sequence data from the mitochondrial (mtDNA) COIII locus, anonymous sequences from the non-recombining portion of the Y chromosome (NRY), and two X chromosomal genes (PDHA1 and RRM2P4). A total of 13.8 kb of DNA sequence was examined in each of 160 individuals from five geographically diverse African populations: the Dinka of Sudan, the Dogon of Mali, the Bakola of Cameroon, and the Khoisan and southeast Bantu from southern Africa.

Estimates of subdivision based on mtDNA and the NRY reveal relatively high levels of population differentiation (FST = 0.284 and 0.236, respectively). Similar levels of population structure for these loci provides no evidence for sex-specific differences in migration rate among these populations. These FST values are only ~20-30% higher than we observe for the same loci sampled in six non-African populations (data not shown). FST values based on the two X chromosome loci (PDHA1 and RRM2P4) were lower (FST = 0.090 and 0.073), but not unexpected because of their 3-fold higher effective population size compared with the haploid loci. These results may be explained by a long period of ongoing gene flow among widely scattered African populations.

Quantitative analysis of modern human and fossil mandibles using 3-D geometric morphometrics.

E. Nicholson et al.

The study of the human mandible has been relatively neglected in comparison to the cranium. Mandibular morphology is often thought to reflect function and not to contain phylogenetic information. Previous descriptions show variation in ramal height and breadth to be the strongest difference among recent human groups. Populations also are thought to vary in corpus robusticity, obliqueness of the ramus, sigmoid notch depth, bicondylar breadth and mental foramen position. Several mandibular traits are believed to differentiate Neanderthals from modern humans: greater robusticity, a receding symphysis, a large retromolar space, a rounder gonial area, an asymmetric sigmoid notch and a posteriorly positioned mental foramen in Neanderthals.

This study quantitatively evaluated some of the proposed differences among modern human groups and between modern and fossil humans and explored these differences to test phylogenetic and functional hypotheses. 28 landmarks were digitized on 134 modern human mandibles from 10 geographic populations. 13 fossil specimens from Europe, the Near East and Africa were also measured. Data were collected with a Microscribe 3DX. A GPA was performed in Morpheus. The fitted coordinates were analyzed in SAS using PCA, CVA, Mahalanobis D2 and Discriminant Analysis. Shape differences were explored using Morphologika.

Modern human mandibular shape shows some geographic patterning. Australians, Polynesians and, to a lesser extent, the Arctic population, are most distinct. Most shape differences between fossil and modern groups, but not among modern humans, are related to differences in centroid size. Functional implications are explored.

Using measures of locus-specific differentiation to find genes underlying traits subject to recent genetic adaptation: a test case using skin pigmentation.

H. Norton et al.

A number of DNA sequence-based statistics are available to identify signatures of natural selection. However, sequencing large numbers of individuals across multiple genes can be costly and time consuming. An alternate method that uses allele frequency data has received less attention, but may be more efficient for large screening studies. This method is based on the idea that demographic events affect loci across the genome equally, while adaptation affects individual genes and nearby markers. We have applied the locus-specific pairwise FST (lspFST) to survey seven pigmentation candidate genes from six geographically diverse populations. Using the allele frequencies at these genes, we calculated the lspFST statistic and compared it to an empirical distribution based on 11,078 SNPs analyzed in the same populations. With this comparison we are able to take into consideration the demographic histories of the populations and calculate likelihoods of the data given neutral evolution. Several pigmentation candidate genes show evidence of non-neutral patterns of differentiation. Interestingly, population differentiation at pigmentation candidate SNPs was observed both for populations differing in pigmentation phenotype (ASIP and OCA2), as well as for populations similar in pigmentation phenotype (TYR). Additionally, SNPs in MATP show high levels of European-specific population differentiation. These results suggest a strong role for natural (and/or sexual) selection in shaping human pigmentation variation. Patterns of allele frequency and lspFST variation at TYR and MATP between Europeans and East Asians raise the possibility that natural selection may have acted on different alleles to produce a similar adaptive phenotype in these populations.

The effect of breastfeeding intensity on bone mineral density.

K. Pearce. University of Massachusetts, Amherst.

Breastfeeding women from Massachusetts (n=35) participated in a study measuring the effect of breastfeeding variation on BMD. Breastfeeding diaries and repeated measures of BMD (DEXA) were used to categorize breastfeeding intensity and changes in BMD throughout the postpartum period. Women entered the study between 2 weeks and 3 years postpartum. The central hypothesis tested was whether variation in breastfeeding intensity affected the rate of change in BMD during lactational amenorrhea (LA) and/or after menses resumed. Multilevel modeling was used to interpret the data. Repeated BMD measures were viewed as nested within individuals. Individuals were nested within groups based on breastfeeding intensity (low, medium-low, medium-high, or high), calcium intake (low or high), and familial history of osteoporosis (yes or no). Results show that BMD decreased during lactation and increased after menses resumed. High breastfeeding intensity had a greater effect on the increase of BMD after menses returned than it had on the loss of bone during LA. High intensity was associated with a .04 g/cm2 increase in BMD (t = 24.1, p=.000) for every three months of post-menses breastfeeding. The same level of breastfeeding intensity during LA was associated with a decrease of .01 g/cm2 BMD, also statistically significant (t = 4.3, p=.01). This study suggests that high intensity post-menses breastfeeding may be an important factor in attaining a net gain in BMD during lactation, with implications for osteoporosis studies of contemporary women and archaeological populations.


Demographic and selective history of African populations inferred from genome wide genetic markers.

F.A. Reed et al.

In collaboration with the Marshfield Medical Research Foundation, a large multi-locus dataset (>2,000,000 genotypes) has been generated from 1,070 microsatellite and in/del markers from ~2,000 individuals originating from >60 ethnically defined populations in Africa and in 100 African Americans. This resource has the potential to answer many questions about the history of humans both within Africa as well as history of the African diaspora into the Americas. These data have been compared to previously published analysis of the same markers in the CEPH diversity panel (Rosenberg et al., 2002). Here we present the results of our analysis of population structure within Africa and African population history. Initial results indicate considerable levels of substructure, even within small geographic regions. We are also able to infer and address several hypotheses regarding the origin of Pygmy populations in Africa, as well as the ancestry of Nilo-Saharan, Niger-Kordofanian, Afro-Asiatic, and Khoisan speaking populations. Additionally, we describe our current efforts at developing acceptance-rejection composite likelihood-approximations to estimate parameters of interest (of demography and selection) from these microsatellite data.

The distribution of ancestral alleles among populations.

A.R. Rogers et al.

The “ancestral allele” at a given locus is the allele thought to have been carried by the last common ancestor (LCA) of all humans. These are only estimates, of course, but they are often relatively good ones. Thus, it is interesting that human ancestral alleles are usually most common in Africa. Some claim that the ancestral allele should be most common in Africa, because it is the ancestral population. We argue otherwise. In the absence of selection or ascertainment bias, the expected frequency of the ancestral allele is the same in each modern population, regardless of the history of population size, subdivision, or gene flow. The observed tendency of ancestral alleles to cluster in Africa argues either for some form of ascertainment bias or for some form of selection.
We attribute the pattern to two forms of ascertainment bias, which affect different sorts of locus. These biases, together with a history of expansion out of Africa, are capable of producing the observed pattern. The only loci that are certainly free of bias are those that sequence arbitrary stretches of DNA far from known genes. In these bias-free systems, there is no tendency for ancestral alleles to be most common in Africa.

Early South Americans in craniofacial metric perspective: Lagoa Santa.

N. Seguchi et al.

We compare the craniofacial morphology of four Sumidouro skulls and one Lund skull, representing South American Paleoindians from Lagoa Santa, Brazil, with worldwide prehistoric and recent human craniofacial metric data. Relationships in these data are illustrated using the neighbor-joining method based on a Mahalanobis distance matrix, discriminant function analysis, canonical variate plots, and posterior and typicality probabilities. We also employed Relethford and Blangero’s R matrix method (Relethford and Blangero 1990, Relethford and Harpending 1994) on the same craniofacial metric data, and generated the neighbor-joining tree and principal coordinate plot. Using Howells’ worldwide comparative dataset, Walter Neves et.al. (2003) recently suggested that Brazilian Paleoamericans probably were closely related to Australian Aborigines and Africans as opposed to Native Americans and Northeast Asians. In contrast, our preliminary results show that Lagoa Santa individuals exhibit stronger morphological affinities with prehistoric Jomon of Japan, recent Patagonia/Tierra del Fuego of South America; present day Mexico, Peru, and Archaic Americans of Windover and Indian Knoll of North America, than with our Australian sample. Moreover, Jomon, Lagoa Santa and Archaic North Americans all present a relatively close relationship, and tie consistently to each other. This suggests that the early inhabitants of South America were probably not related to Australo-Melanesians, but rather the Late Pleistocene descendents of Northeast Asia, such as Jomon. Also, they are related to the Archaic North American populations and recent central, and South Americans.

History of modern human population structure inferred from the worldwide survey on Xp11.22 sequences.

M. K. Shimada et al.

For study of human evolution, using DNA sequence data, long lengths are required because of low mutation rates. However long sequences have a higher probability that recombination has occurred in the region in the evolutionary history. On the other hand, microsatellite data have a high mutation rate but tend to have too much homoplasy. The limitations of different types of data are one reason why different studies have different conclusions regarding human evolutionary history.

We sequenced a 10.1-kilobase pair region of the X chromosome, from 650 individuals from 50 populations. The sequenced region includes two microsatellites. The conjunction of sequence variation with tightly linked microsatellite variation allows each type of data to overcome the limitations of the other.

We found very little evidence of recombination within the region. Most sequences are quite similar to one another, however three sequences differed from the others at an average of 28.6 substitutions. Assuming a molecular clock, and a human/chimpanzee divergence time of 6 million years, the estimated age of the base of the human sequences is 1.1 million years ago, whereas the estimated base of the tree excluding these divergent human sequences is 290,000 years ago. These divergent sequences were found in samples from the Middle East (Druze and Bedouin populations) and North Africa (Mozabite population). The pattern is suggestive of admixture between non-African Archaic humans and Modern Humans.

Demographic history of African populations inferred from mtDNA analysis.

S.A. Tishkoff et al.

The continent of Africa is thought to be the homeland of all modern humans; it contains the largest amount of human genetic variation, both within and between populations, and the oldest genetic lineages. We have collected an unparalleled resource of genomic DNA samples from >4000 individuals originating from ethnically defined populations across Africa. At the same time, extensive pedigree, linguistic, ethnic, geographic and physiological data was also recorded for many of these individuals. Here we describe our analysis of mtDNA variation obtained from sequencing 1200bp of the control region and genotyping 6 coding-region SNPs mtDNA analysis of a subset of coding-region SNPs in 650 ethnically diverse Tanzanians and from sequencing 40 whole mtDNA genomes (~16,000 bp/genome). We have used coalescence based maximum likelihood simulations to estimate multiple demographic parameters including historic population size, bi-directional migration, time of population divergence, and time of most recent common ancestry of DNA lineages from these data. We observe recent gene flow between populations and phylogenetic analyses show that Tanzanian mtDNA lineages form the most basal branches of the global mitochondrial tree, suggesting that the range expansion of modern humans may have originated in East Africa. Additionally, we find common ancestry of the Hadza and Sandawe Khoisan (click)-speaking populations of Tanzania and that the Sandawe have had historical gene flow and/or common ancestry with southern African !Kung San, supporting the hypothesis that Khoisan speakers may have originated in East Africa.

On the origins of strong polygyny and socially imposed monogamy in humans.

C.P. van Schaik et al.

Because humans show pair-bonding, the environmental potential for despotism is reflected in social polgyny. We first show that increased despotism is expected under a general primate model of male-male coalitions, where the egalitarian system of mobile hunter-gatherers, maintained by large-scale leveling coalitions, is replaced by a despotic system with violent, revolutionary coalitionary takeovers of top ranks. Humans also differ from the other primates in that groups are spatially subdivided, which can produce cliques or class structure. Historically, however, some societies have shown a return to more egalitarian social relationships among males. We present a concession model, in which high-ranking males recruit support from lower-ranking males by granting them more reproductive success. A critical prediction is that transitions to social monogamy or dissolution of castes are found in societies under enemy occupation or involved in a desperate war.

In this paper we investigate the importance of predators in limiting primate populations by testing the following predictions using data taken from the primate literature. First, we predict that habituated primate populations experiencing reduced predation risk due to continuous human presence increase in numbers, at least during the initial years of human presence, whereas unhabituated populations do not. Second, we predict that population densities of primate species in otherwise similar forests in which carnivore predators have disappeared should be lower than those in forests with predators. The results allow us to estimate the relative magnitude of the effect of carnivore predators on primate populations. We discuss the implications of these results for primate population ecology and conservation biology.

A mesio-buccal mandibular molar trait in ancient populations of Ireland.

J.D. Weets

In this poster, previously unpublished variation of a human dental trait in permanent mandibular molars is described. The character, presently labeled IMMP (the Irish Mandibular Molar Pit), is situated anterior to the position occupied by the protostylid on the buccal aspect of cusp 1, and is most commonly found on third molars. IMMP occurred in 32.6% of 126 lower right third molars and 28.3% of 131 lower left third molars from archaeological specimens dating to the Neolithic (c. 4000-1800 BC) through the Early Christian era (c. AD 400-1170) in Ireland. The character was tested for variation in its geographic and temporal distribution across the island. No significant differences were found in its occurrence between time periods, nor between regions of Ireland. But, a lack of significant variation between the island’s ancient populations in other dental traits has been noted by the author in further research. Interestingly, an individual Viking specimen from Ireland exhibited IMMP. Personal correspondence with another dental anthropologist suggests the trait is present, at a much lower rate of expression, in East Asian populations (approximately 1-2% of his sample). These two findings indicate a widespread geographic occurrence that prompts more investigation of IMMP in other populations. Furthermore, marked difference of expression between populations from Ireland and East Asia suggest the trait will distinguish, at the very least, distant geographical populations and may make IMMP a useful addition to the suite of morphological traits utilized by dental anthropologists in biodistancing studies.

Mitochondrial DNA Variation in Northern Altaians: affinities with Siberian and Turkic populations.

S.I. Zhadanov et al.

Altaian peoples are the descendants of ancient (non-Turkic) inhabitants of this mountainous area who mixed with various waves of Turkic speaking nomads, beginning about 2,000 years ago. They are divided into northern and southern groups that are known to be physically, culturally and linguistically distinctive. Morphologically, the Southern Altai-kizhi generally exhibit stronger affinities with Mongolian and East Asian groups, whereas Northern Altaians, including Tubalars, Chelkans and Kumandinians, show some affinities with West Eurasian and Uralic groups. Initial genetic studies involving Altai-kizhi tribes have also revealed them to have considerable genetic diversity with influences from both West and East Eurasian populations. However, Northern Altaian groups as a whole are less well genetically characterized. To clarify this pattern of biological diversity in the Altai region, we surveyed mtDNA variation in several Northern Altaians population from the Altai Republic, and compared the resulting data with the Altai-kizhi and other Siberian and Turkic speaking groups from the region. In addition, we combined the extensive genealogical and demographic data with the mtDNA data from these populations to more accurately reconstruct the prehistory of the Altai Mountain region, including the assessment of Altaian population structure as reckoned by oral histories and tribal clan (seok) membership.