Ancient DNA for horse coat color

In the early Holocene, horses were either bay or black, but then a large number of variations started to accumulate.

In contrast, a rapid and substantial increase in the number of coat colorations is found in both Siberia and East Europe beginning in the fifth millennium B.P. (Fig. 1 and figs. S1 and S2). Although the earliest chestnut allele (MC1R gene) was identified in a Romanian sample from the late seventhmillennium B.P., chestnut horses were first observed in Siberia (fifth millenium B.P.). Their prevalence increased rapidly, reaching 28% during the Bronze Age.

The earliest chestnut allele comes from a wild horse from Pietrele, a village in southern Romania (4,300BC). But, since this horse was heterozygous in the MC1R locus and homozygous in the ASIP locus for the black allele, it exhibited a black coat color.

Interestingly, in the Eneolithic, the 4 Romanian horses were all black, while 5 Ukrainian samples from Mayaki were bay, and 1 from Molyukhov Bugor was black.

The first observed chestnut horse was from Tartas-1 in West Siberia (3,000-2,500BC).

More:

Mutations responsible for coat color dilutions or spottings seem to appear later. Cream (buckskin) and (black) silver dilutions (2800 to 2600 yr B.P.) were first observed in Siberia. Sabino is the first spotting phenotype, appearing during the
fifth millennium B.P. in Siberia, and present in Armenia and Moldavia during the middle Bronze Age. The Tobiano spotting was first found in a single Eastern European sample (3500 to 3000 yr B.P.) and later also in Asia. Unlike in samples from Siberia and Eastern Europe, we observed no color change in Spanish samples until medieval times.

Sabino spotting was first observed in Tartas-1 from West Siberia (3,000-2,500BC) and then in Lchasen Armenia (1,410-1,250BC) and then Miciurin, Moldova (1,500-1,000BC).

Tobiano spotting was also first observed in Miciurin, and later in Arzan-2 from Irona Age South Siberia (619-608BC).

Related:

• Earliest horse domestication in Kazakhstan
• Origin of ancient Chinese horses from ancient DNA
• Equine coat color genetics

[Image of a copper-red chestnut horse.]

Science doi: 10.1126/science.1172750

Coat Color Variation at the Beginning of Horse Domestication

Arne Ludwig et al.

Abstract

The transformation of wild animals into domestic ones available for human nutrition was a key prerequisite for modern human societies. However, no other domestic species has had such a substantial impact on the warfare, transportation, and communication capabilities of human societies as the horse. Here, we show that the analysis of ancient DNA targeting nuclear genes responsible for coat coloration allows us to shed light on the timing and place of horse domestication. We conclude that it is unlikely that horse domestication substantially predates the occurrence of coat color variation, which was found to begin around the third millennium before the common era.

Link

mtDNA haplogroup T and coronary artery disease/diabetic retinopathy

BMC Med Genet. 2009 Apr 21;10(1):35. [Epub ahead of print]

Mitochondrial DNA haplogroup T is associated with coronary artery disease and diabetic retinopathy: a case control study.

Kofler B, et al.

ABSTRACT: BACKGROUND: There is strong and consistent evidence that oxidative stress is crucially involved in the development of atherosclerotic vascular disease. Overproduction of reactive oxygen species (ROS) in mitochondria is an unifying mechanism that underlies micro- and macrovascular atherosclerotic disease. Given the central role of mitochondria in energy and ROS production, mitochondrial DNA (mtDNA) is an obvious candidate for genetic susceptibility studies on atherosclerotic processes. We therefore examined the association between mtDNA haplogroups and coronary artery disease (CAD) as well as diabetic retinopathy. METHODS: This study of Middle European Caucasians included patients with angiographically documented CAD (n=487), subjects with type 2 diabetes mellitus with (n=149) or without (n=78) diabetic retinopathy and control subjects without clinical manifestations of atherosclerotic disease (n=1527). MtDNA haplotyping was performed using multiplex PCR and subsequent multiplex primer extension analysis for determination of the major European haplogroups. Haplogroup frequencies of patients were compared to those of control subjects without clinical manifestations of atherosclerotic disease. RESULTS: Haplogroup T was significantly more prevalent among patients with CAD than among control subjects (14.8% vs 8.3%; p=0.002). In patients with type 2 diabetes, the presence of diabetic retinopathy was also significantly associated with a higher prevalence of haplogroup T (12.1% vs 5.1%; p=0.046). CONCLUSION: Our data indicate that the mtDNA haplogroup T is associated with CAD and diabetic retinopathy in Middle European Caucasian populations.

Link

On the edge of Bantu expansions in southwestern Angola

From the paper:

Divergence time estimates were remarkably consistent with the archeological data (t=4000 years; Table 4)

Not surprisingly, the authors used a germline mutation rate rather than the problematic "evolutionary" rate which has misled so many researchers.

BMC Evol Biol doi:10.1186/1471-2148-9-80

On the edge of Bantu expansions: mtDNA, Y chromosome and lactase persistence genetic variation in southwestern Angola.

Margarida Coelho et al.

Abstract

Background

Current information about the expansion of Bantu-speaking peoples is hampered by the scarcity of genetic data from well identified populations from southern Africa. Here, we fill an important gap in the analysis of the western edge of the Bantu migrations by studying for the first time the patterns of Y-chromosome, mtDNA and lactase persistence genetic variation in four representative groups living around the Namib Desert in southwestern Angola (Ovimbundu, Ganguela, Nyaneka-Nkumbi and Kuvale). We assessed the differentiation between these populations and their levels of admixture with Khoe-San groups, and examined their relationship with other sub-Saharan populations. We further combined our dataset with previously published data on Y-chromosome and mtDNA variation to explore a general isolation with migration model and infer the demographic parameters underlying current genetic diversity in Bantu populations.

Results

Correspondence analysis, lineage sharing patterns and admixture estimates indicate that the gene pool from southwestern Angola is predominantly derived from West-Central Africa. The pastoralist Herero-speaking Kuvale people were additionally characterized by relatively high frequencies of Y-chromosome (12%) and mtDNA (22%) Khoe-San lineages, as well as by the presence of the -14010C lactase persistence mutation (6%), which likely originated in non-Bantu pastoralists from East Africa. Inferred demographic parameters show that both male and female populations underwent significant size growth after the split between the western and eastern branches of Bantu expansions occurring 4000 years ago. However, males had lower population sizes and migration rates than females throughout the Bantu dispersals.

Conclusions

Genetic variation in southwestern Angola essentially results from the encounter of an offshoot of West-Central Africa with autochthonous Khoisan-speaking peoples from the south. Interactions between the Bantus and the Khoe-San likely involved cattle herders from the two groups sharing common aspects of their social organization. The presence of the -14010C mutation in southwestern Angola provides a link between the East and Southwest African pastoral scenes that might have been established indirectly, through migrations of Khoe herders across southern Africa. Differences in patterns of mtDNA and Y-chromosome intrapopulation diversity and interpopulation differentiation may be explained by contrasting demographic histories underlying the current female and male genetic variation.

Link

mtDNA of ethnic groups of Reunion Island

From the paper:

As a result of the different immigration waves and the cultural and socio-economic interactions, six main ethnic groups emerged in Reunion Island: the Créoles Blancs (of European major ancestry), the Kaf (of African and Malagasy major ancestry), the Malbar (of Indian major ancestry), the Créoles Métis (of mixed ancestry), the Shinwa (of South-eastern Chinese ancestry) and the Zarab (of Gujarati ancestry). These ethnic groups are defined here according to the 'nomenclature' used by Reunionese themselves (Médéa, 2002, 2004).

Table S5 has the mtDNA results.

Annals of Human Genetics doi:10.1111/j.1469-1809.2009.00519.x

Inter- and Extra-Indian Admixture and Genetic Diversity in Reunion Island Revealed by Analysis of Mitochondrial DNA

Vincent Dubut et al.

Abstract

Reunion Island is a French territory located in the western Indian Ocean. The genetic pattern of the Reunionese population has been shaped by contributions from highly contrasting regions of the world. Over the last 350 years, several migration waves and cultural and socio-economic factors have led to the emergence of six main ethnic groups in Reunion. India is one of the principal regions that contributed to the setting up of the Reunionese population. Diversity, demographic and admixture analyses were performed on mtDNA variation of the Reunionese of Indian ancestry, including the Malbar and Zarab ethnic groups, in order to question their history. Using a phylogeographical approach, we generated and analysed quantitative data on the contribution of the Indian parental populations. Furthermore, we showed that the settlement of Reunion Island by Indians did not involve a founder effect, except in the very beginning of the Reunionese settlement (at the end of the 17th century). The accuracy of our results was optimised by a re-evaluation of the classification of the Southern Asian mtDNA haplogroups. Finally, by comparing our results to a previous study dealing with the Reunionese population, we highlighted how ethno-historical data are critical for reconstructing the complex history of multiethnic populations.

Link

Geometric morphometric quantification of Sub-Saharan cranial variation

American Journal of Human Biology doi:10.1002/ajhb.20908

A geometric morphometric approach to the quantification of population variation in sub-Saharan African crania

Daniel Franklin et al.

Abstract

We report here on new data examining cranial variation in 18 modern human sub-Saharan African populations. Previously, we investigated variation within southern Africa; we now extend our analyses to include a series of Central, East, and West African crania, to further knowledge of the relationships between, and variation and regional morphological patterning in, those populations. The sample comprises 377 male individuals; the three-dimensional coordinates of 96 landmarks are analyzed using Procrustes-based methods. Interpopulation variation is examined by calculating shape distances between groups, which are compared using resampling statistics and parametric tests. Phenotypic variance, as a proxy for genetic variance, is measured and compared across populations. Principal components and cluster analyses are employed to explore relationships between the populations. Shape differences are visualized using three-dimensional rendered models. Observed disparity patterns imply a mix of differences and similarities across populations, with no apparent support for genetic bottlenecks, which is likely a consequence of migrations that may have influenced differences in cranial form; supporting data are found in recent molecular studies. The Pygmy sample had the most distinctive cranial morphology; characteristically small in size with marked prognathism. These features characterized, although less strongly, the neighboring Bateke, and are possibly related to similar selective pressures in conjunction with interbreeding. Small cranial size is also involved in the considerable distinctiveness of the San and Khoikhoi. The statistical procedures applied in this study afford a powerful and robust means of quantifying and visualizing the magnitude and pattern of cranial variation between sub-Saharan African populations.

Link

Tayinat Dark Age temple

The website of the Tayinat Archaeological Project, and project background (pdf).

UPDATE (Apr 30): National Geographic reports on "Dark Age" Temple found in Turkey.

University of Toronto archeologists discover temple that sheds light on so-called Dark Age
:

The discovery of a remarkably well-preserved monumental temple in Turkey — thought to be constructed during the time of King Solomon in the 10th/9th-centuries BC — sheds light on the so-called Dark Age.

Uncovered by the University of Toronto's Tayinat Archaeological Project (TAP) in the summer of 2008, the discovery casts doubt upon the traditional view that the transition from the Late Bronze Age to the Early Iron Age was violent, sudden and culturally disruptive.

Ancient sources — such as the Homeric epics and the Hebrew Bible — depict an era of widespread famine, ethnic conflict and population movement, most famously including the migrations of the Sea Peoples (or biblical Philistines) and the Israelites. This is thought to have precipitated a prolonged Dark Age marked by cultural decline and ethnic strife during the early centuries of the Iron Age. But recent discoveries — including the Tayinat excavations — have revealed that some ruling dynasties survived the collapse of the great Bronze Age powers.

"Our ongoing excavations have not only begun to uncover extensive remains from this Dark Age, but the emerging archaeological picture suggests that during this period Tayinat was the capital of a powerful kingdom, the 'Land of Palastin'," says Timothy Harrison, professor of Near Eastern Archaeology at the University of Toronto and the director of the project. "Intriguingly, the early Iron Age settlement at Tayinat shows evidence of strong cultural connections, if not the direct presence of foreign settlers, from the Aegean world, the traditional homeland of the Sea Peoples."

Climate and human tuberculosis

Interdiscip Perspect Infect Dis. doi: 10.1155/2009/437187

Paleopathology of Human Tuberculosis and the Potential Role of Climate

Andreas G. Nerlich and Sandra Lösch

Abstract

Both origin and evolution of tuberculosis and its pathogens (Mycobacterium tuberculosis complex) are not fully understood. The paleopathological investigation of human remains offers a unique insight into the molecular evolution and spread including correlative data of the environment. The molecular analysis of material from Egypt (3000–500 BC), Sudan (200–600 AD), Hungary (600–1700 AD), Latvia (1200–1600 AD), and South Germany (1400–1800 AD) urprisingly revealed constantly high frequencies of tuberculosis in all different time periods excluding significant environmental influence on tuberculosis spread. The typing of various mycobacteria strains provides evidence for ancestral M. tuberculosis strains in Pre- to early Egyptian dynastic material (3500–2650 BC), while typical M. africanum signatures were detected in a Middle Kingdom tomb (2050–1650 BC). Samples from the New Kingdom to Late Period (1500–500 BC) indicated modern M. tuberculosis strains. No evidence was seen for M. bovis in Egyptian material while M. bovis signatures were first identified in Siberian biomaterial dating 2000 years before present. These results contraindicates the theory that M. tuberculosis evolved from M. bovis during early domestication in the region of the “Fertile Crescent,” but supports the scenario that M. tuberculosis probably derived from an ancestral progenitor strain. The environmental influence of this evolutionary scenario deserves continuing intense evaluation.

Link

Political complexity and the spread of ethnolinguistic groups

Gene Expression points me to a new paper on the spread of languages. From the paper:

In particular we have shown that the largest single factor predicting the area over which a language is spoken is the degree of political complexity exhibited by the society speaking that language. This is consistent with the hypothesis that more complex societies replace or incorporate less complex groups and thus spread their languages over larger areas. As political complexity is a property of groups, and
competition often occurs between groups, rather than just between individuals, if more politically complex groups tend to replace or incorporate others, then the proportion of more politically complex societies will tend to increase over time. Such a mechanism represents a process of cultural group selection (21, 48). An interesting area for future research will be to assess the impact this process has on the biological fitness of individuals within groups (49). Increasing political complexity is almost
always associated with greater degrees of social stratification, and wealth in the form of tax or tribute is often extracted by political elites from those lower down the social order (24), which could clearly have significant reproductive consequences for individuals at different levels in such societies. It will be important to assess empirically whether these costs are outweighed by benefits gained from being a member of such a group and from the advantage held in competition between groups.

PNAS doi:10.1073/pnas.0804698106

Political complexity predicts the spread of ethnolinguistic groups

Thomas E. Currie and Ruth Mace

Abstract

Human languages show a remarkable degree of variation in the area they cover. However, the factors governing the distribution of human cultural groups such as languages are not well understood. While previous studies have examined the role of a number of environmental variables the importance of cultural factors has not been systematically addressed. Here we use a geographical information system (GIS) to integrate information about languages with environmental, ecological, and ethnographic data to test a number of hypotheses that have been proposed to explain the global distribution of languages. We show that the degree of political complexity and type of subsistence strategy exhibited by societies are important predictors of the area covered by a language. Political complexity is also strongly associated with the latitudinal gradient in language area, whereas subsistence strategy is not. We argue that a process of cultural group selection favoring more complex societies may have been important in shaping the present-day global distribution of language diversity.

Link

In search of Bronze Age metal prospectors

UPDATE:

A post in the GENEALOGY-DNA-L gives some additional information from the scientists working on this:

We are following up on the Weale study (Mol. Biol. Evol. 19(7):1008-1021. 2002) which reported a much higher than average number of E3b individuals in
Abergele. We are interested in the possibility that these may be linked to
the Bronze age copper mines nearby, but obviously this is just one
possibility. The first step is to see if we can replicate the findings of
the 2002 study in a much larger sample.

The 2002 study had found a high frequency of HG21 in Abergele. It will be interesting to see which subclade of E3b (or E1b1b in the updated terminology) the NW Wales men belong to. If they do belong to E-V13, then this would be consistent with a Bronze Age origin, although this would be difficult to distinguish from other scenaria, e.g., the arrival of this haplogroup with the Romans.

Also of interest: The Litoroid Race in the Bronze Age.

DNA test to prove Bronze Age link

Men are needed for DNA tests to prove their distant ancestors moved from the Mediterranean to north west Wales as migrant workers 4,000 years ago.

...

Researchers at the University of Sheffield hope to link the migration of men in the Bronze Age to the discovery of copper.

The metal was found at both Parys Mountain on Anglesey, and on the Great Orme at Llandudno, Conwy.

The researchers are building on previous work carried out in the area which found a much higher-than-average presence of a DNA marker that is commonly found in people from the Balkans and Spain.

Happy Easter

Paternal traces of Bantu expansion + African R1b1 mystery

It's good to see a paper which doesn't use an effective mutation rate to estimate ages, so the reported ages in this paper are more believable than the norm.

Expansion times and their standard deviations were calculated using eleven STRs (DYS19, DYS389I, DYS389II DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS460), whose mutation rates have been individually estimated (Gusmao et al. 2005). The allelic variance of each STR was divided by the estimated mutation rate, and the mean of the variances was multiplied by 25 (intergeneration time in years).

The main haplogroups found were:

Specifically, most of these lineages have been associated either to Bantu-speaking people - E1b1a (E3a according to The Y Chromosome Consortium (2002)), B2a, and E2 - or to Pygmy populations (haplogroup B2b). We also observed traces of haplogroups A, E*, E1a, and E1b1b1a (E3b1 according to The Y Chromosome Consortium (2002)), which are found at low frequencies across the African continent (Underhill et al. 2000; Underhill et al. 2001; Cruciani et al. 2002; Wood et al. 2005). Interestingly, almost 5% of the individuals here analyzed belonged to Eurasian haplogroup R1b1*.

If a correct mutation rate is used and a star-like signal of expansion is visible, then, not surprisingly, archaeology does correlate with haplogroup expansion:

The expansion date of the E1b1a haplogroup was estimated at 5,800 years (SD 7,200), in agreement with the expansion of Bantu languages.

The R1b1*-in-Africa mystery thickens. At first, these typically Eurasian chromosomes had been found in Cameroon, but they seem to be found in many populations

A remarkable finding of our study is the substantial number of individuals belonging to haplogroup R1b1* (5.2%). Surprisingly, it has been previously observed in northern Cameroon (40%) at high frequencies (Cruciani et al. 2002), and at lower frequencies in southern Cameroon (1.12%) (Cruciani et al. 2002), Oman (1%), Egypt
(2%), Hutu from Rwanda (1%) (Luis et al. 2004). The presence of this lineage in Africa has been claimed to be a genetic signature of a possible backflow migration from west Asia into Africa (Cruciani et al. 2002). Here we observe R1b1* in 12 Bantu
agriculturalist populations (ranging from 2% to 20%) and in two Pygmy individuals. A
network of R1b1* haplotypes performed using STR-data (Figure 2) shows two main
clusters, without any population structure. Interestingly, the estimated expansion time for these haplotypes – 7,000 years (SD 8,100) - precedes the time at which the Bantu expansion occurred.

...

It is noteworthy that the Fang population is the Bantu agriculturalist group presenting the highest frequency of R1b1*. The presence of the Fang in west Central Africa appears to be recent and they 20 are thought to have entered the region from the north-eastern open grassland plateau during the 17th and 18th centuries (Perrois 2006).

It would certainly be worthwhile for R1b1 experts to take a look at the haplotypes found in the region (Supplementary Table 1), and to see how they are related to R1b1 elsewhere.

Molecular Biology and Evolution, doi:10.1093/molbev/msp069

Genetic and demographic implications of the Bantu expansion: insights from human paternal lineages

Gemma Berniell-Lee et al.

Abstract

The expansion of Bantu languages, which started around 5,000 years before present (YBP) in west/central Africa and spread all throughout sub-Saharan Africa, may represent one of the major and most rapid demographic movements in the history of the human species. Although the genetic footprints of this expansion have been unmasked through the analyses of the maternally-inherited mitochondrial (mtDNA) lineages, information on the genetic impact of this massive movement and on the genetic composition of pre-Bantu populations is still scarce. Here we analyze an extensive collection of Y-chromosome markers - 41 SNPs and 18 STRs - in 883 individuals from 22 Bantu-speaking agriculturalist populations and 3 Pygmy hunter-gatherer populations from Gabon and Cameroon. Our data reveal a recent origin for most paternal lineages in west Central African populations most likely resulting from the expansion of Bantu-speaking farmers that erased the more ancient Y-chromosome diversity found in this area. However, some traces of ancient paternal lineages are observed in these populations, mainly among hunter-gatherers. These results are at odds with those obtained from mtDNA analyses, where high frequencies of ancient maternal lineages are observed, and substantial maternal gene flow from hunter-gatherers to Bantu farmers has been suggested. These differences are most likely explained by socio-cultural factors such as patrilocality. We also find the intriguing presence of paternal lineages belonging to Eurasian haplogroup R1b1*, which might represent footprints of demographic expansions in central Africa not directly related to the Bantu expansion.

Link

Three Geographical groups among Neanderthals

I have to wonder: how come we already have 15 Neandertal mtDNA sequence and less than a handful of Pleistocene Homo sapiens? My guess is that the latter may often turn out to be more similar to extant human mtDNA, making them more "suspect" for contamination.

Figure 2 shows the three Neandertal groups.

PLoS ONE doi:10.1371/journal.pone.0005151

Genetic Evidence of Geographical Groups among Neanderthals

Virginie Fabre et al.

Abstract

The Neanderthals are a well-distinguished Middle Pleistocene population which inhabited a vast geographical area extending from Europe to western Asia and the Middle East. Since the 1950s paleoanthropological studies have suggested variability in this group. Different sub-groups have been identified in western Europe, in southern Europe and in the Middle East. On the other hand, since 1997, research has been published in paleogenetics, carried out on 15 mtDNA sequences from 12 Neanderthals. In this paper we used a new methodology derived from different bioinformatic models based on data from genetics, demography and paleoanthropology. The adequacy of each model was measured by comparisons between simulated results (obtained by BayesianSSC software) and those estimated from nucleotide sequences (obtained by DNAsp4 software). The conclusions of this study are consistent with existing paleoanthropological research and show that Neanderthals can be divided into at least three groups: one in western Europe, a second in the Southern area and a third in western Asia. Moreover, it seems from our results that the size of the Neanderthal population was not constant and that some migration occurred among the demes.

Link

Major new paper on Y-chromosome haplogroup J1-M267 by Tofanelli et al.

The supplementary material are free online. Figure S1 is particularly interesting since it shows an inverse correlation between gene diversity and J1-M267 frequency in the studied populations.

The paper starts off well:

However, a wide range of times since the most recent common ancestor (TMRCAs) has been proposed for J1 and its subclades (between 36 and 10 KyBP), and different conflicting scenarios have been depicted to explain their current distribution.

Unfortunately I wasn't able to locate in the paper/supp info any mention of the mutation rate assumed in this paper which leads the authors to come out in support of a pre-historical "hunter-gatherer" mode of dispersal for J1. Naturally I'm very skeptical of archaeological conclusions based on TMRCA, both because most of the literature leads to age overestimates, and because population movements may be both older and younger than TMRCAs, and TMRCAs of modern Y-chromosomes tell us virtually nothing about them.

UPDATE (Apr 21): A reader alerts me of the fact that the mutation rate is shown in Supplementary Table 4, where a uniform distribution between the germline (0.0028) and "evolutionary" rate (0.00069) is assumed. As I don't think there is any merit to the evolutionary rate for large haplogroups, the ages presented in the paper should be divided by ~1.5, although as always, these carry fairly wide uncertainty margins.

European Journal of Human Genetics doi:10.1038/ejhg.2009.58

J1-M267 Y lineage marks climate-driven pre-historical human displacements

Sergio Tofanelli et al.

Abstract

The present day distribution of Y chromosomes bearing the haplogroup J1 M267^*G variant has been associated with different episodes of human demographic history, the main one being the diffusion of Islam since the Early Middle Ages. To better understand the modes and timing of J1 dispersals, we reconstructed the genealogical relationships among 282 M267^*G chromosomes from 29 populations typed at 20 YSTRs and 6 SNPs. Phylogenetic analyses depicted a new genetic background consistent with climate-driven demographic dynamics occurring during two key phases of human pre-history: (1) the spatial expansion of hunter gatherers in response to the end of the late Pleistocene cooling phases and (2) the displacement of groups of foragers/herders following the mid-Holocene rainfall retreats across the Sahara and Arabia. Furthermore, J1 STR motifs previously used to trace Arab or Jewish ancestries were shown unsuitable as diagnostic markers for ethnicity.

Link

Genes of Finns revisited

This paper interprets the discrepancy between Y-chromosome and mtDNA results in Finland as the signature of Scandinavian gene flow into the western parts of the country, with the Y-chromosome gene pool of the east (typified by haplogroup N3) preserving the original inhabitants starting from the Holocene deglaciation.

It it is not at all clear, however "who got there first", and as far as I can see, the evidence just tells us there is a substantial east-west difference in Y-chromosomes in Finland, it doesn't really tell us which of the two elements represents the most ancient stratum.

In my opinion, the Finnish gene pool may contain traces of the aboriginal inhabitants, as well as the later eastern elements which brought the Finnish language, and the later still influences by Germanic Scandinavians. Hopefully the northern cold has been generous with DNA preservation and we may get some direct glimpses into the country's genetic history.

Some related posts:

• Genomic substructure in Finns
• Migrations in the Baltic region inferred from Y chromosomes and mtDNA
• Y chromosome variation of Finns

European Journal of Human Genetics doi:

Genetic markers and population history: Finland revisited

Jukka U Palo et al.

Abstract

The Finnish population in Northern Europe has been a target of extensive genetic studies during the last decades. The population is considered as a homogeneous isolate, well suited for gene mapping studies because of its reduced diversity and homogeneity. However, several studies have shown substantial differences between the eastern and western parts of the country, especially in the male-mediated Y chromosome. This divergence is evident in non-neutral genetic variation also and it is usually explained to stem from founder effects occurring in the settlement of eastern Finland as late as in the 16th century. Here, we have reassessed this population historical scenario using Y-chromosomal, mitochondrial and autosomal markers and geographical sampling covering entire Finland. The obtained results suggest substantial Scandinavian gene flow into south-western, but not into the eastern, Finland. Male-biased Scandinavian gene flow into the south-western parts of the country would plausibly explain the large inter-regional differences observed in the Y-chromosome, and the relative homogeneity in the mitochondrial and autosomal data. On the basis of these results, we suggest that the expression of 'Finnish Disease Heritage' illnesses, more common in the eastern/north-eastern Finland, stems from long-term drift, rather than from relatively recent founder effects.

Link

Inbreeding and the Spanish Hapsburgs

Since, presumably, the remains of these royals have been preserved, it would be interesting at some future date to carry out an ancient DNA study which would show exactly which deleterious alleles contributed to the morbidity of the Spanish Hapsburgs.

PLoS ONE doi:10.1371/journal.pone.0005174

The Role of Inbreeding in the Extinction of a European Royal Dynasty

Gonzalo Alvarez et al.

Abstract

The kings of the Spanish Habsburg dynasty (1516–1700) frequently married close relatives in such a way that uncle-niece, first cousins and other consanguineous unions were prevalent in that dynasty. In the historical literature, it has been suggested that inbreeding was a major cause responsible for the extinction of the dynasty when the king Charles II, physically and mentally disabled, died in 1700 and no children were born from his two marriages, but this hypothesis has not been examined from a genetic perspective. In this article, this hypothesis is checked by computing the inbreeding coefficient (F) of the Spanish Habsburg kings from an extended pedigree up to 16 generations in depth and involving more than 3,000 individuals. The inbreeding coefficient of the Spanish Habsburg kings increased strongly along generations from 0.025 for king Philip I, the founder of the dynasty, to 0.254 for Charles II and several members of the dynasty had inbreeding coefficients higher than 0.20. In addition to inbreeding due to unions between close relatives, ancestral inbreeding from multiple remote ancestors makes a substantial contribution to the inbreeding coefficient of most kings. A statistically significant inbreeding depression for survival to 10 years is detected in the progenies of the Spanish Habsburg kings. The results indicate that inbreeding at the level of first cousin (F = 0.0625) exerted an adverse effect on survival of 17.8%±12.3. It is speculated that the simultaneous occurrence in Charles II (F = 0.254) of two different genetic disorders: combined pituitary hormone deficiency and distal renal tubular acidosis, determined by recessive alleles at two unlinked loci, could explain most of the complex clinical profile of this king, including his impotence/infertility which in last instance led to the extinction of the dynasty.

Link

Facebook-using college students get lower grades

The question is: is Facebook responsible for distracting students from studying, or do students who would rather not study anyway spend more time on Facebbok? I am inclined to favor the latter explanation.

Facebook Use Linked To Lower Grades In College

College students who use Facebook spend less time studying and have lower grade point averages than students who have not signed up for the social networking website, according to a pilot study at one university.

However, more than three-quarters of Facebook users claimed that their use of the social networking site didn’t interfere with their studies.

“We can’t say that use of Facebook leads to lower grades and less studying – but we did find a relationship there,” said Aryn Karpinski, co-author of the study and a doctoral student in education at Ohio State University.

“There’s a disconnect between students’ claim that Facebook use doesn’t impact their studies, and our finding showing they had lower grades and spent less time studying.”

...

The researchers surveyed 219 students at Ohio State, including 102 undergraduate students and 117 graduate students. Of the participants, 148 said they had a Facebook account.

...

“It may be that if it wasn’t for Facebook, some students would still find other ways to avoid studying, and would still get lower grades. But perhaps the lower GPAs could actually be because students are spending too much time socializing online.”