Showing posts with label N1a. Show all posts
Showing posts with label N1a. Show all posts

May 03, 2015

Structure of Y-haplogroup N

arXiv:1504.06463 [q-bio.PE]

The dichotomy structure of Y chromosome Haplogroup N

Kang Hu et al.

Haplogroup N-M231 of human Y chromosome is a common clade from Eastern Asia to Northern Europe, being one of the most frequent haplogroups in Altaic and Uralic-speaking populations. Using newly discovered bi-allelic markers from high-throughput DNA sequencing, we largely improved the phylogeny of Haplogroup N, in which 16 subclades could be identified by 33 SNPs. More than 400 males belonging to Haplogroup N in 34 populations in China were successfully genotyped, and populations in Northern Asia and Eastern Europe were also compared together. We found that all the N samples were typed as inside either clade N1-F1206 (including former N1a-M128, N1b-P43 and N1c-M46 clades), most of which were found in Altaic, Uralic, Russian and Chinese-speaking populations, or N2-F2930, common in Tibeto-Burman and Chinese-speaking populations. Our detailed results suggest that Haplogroup N developed in the region of China since the final stage of late Paleolithic Era.

Link

September 04, 2014

Y chromosomes and mtDNA of early farmers from Hungary

A new preprint has just appeared on the bioRxiv. It's free to read so I'll just summarize some results. First:
The haplotype of the Mesolithic skeleton from the Croatian Island Korčula belongs to the mtDNA haplogroup U5b2a5 (Dataset S3). The sub-haplogroup U5b has been shown to be frequent in pre-Neolithic hunter-gatherer communities across Europe [28–30,32,33,45,46]. 
But:
Contrary to the low mtDNA diversity reported from hunter-gatherers of Central/North Europe [28–30], we identify substantially higher variability in early farming communities of the Carpathian Basin  including the haplogroups N1a, T1, T2, J, K, H, HV, V, W, X, U2, U3, U4, and U5a (Table 1). Previous studies have shown that haplogroups N1a, T2, J, K, HV, V, W and X are most characteristic for the Central European LBK and have described these haplogroups as the mitochondrial ʻNeolithic packageʼ that had reached Central Europe in the 6th millennium BC [36,37]. Interestingly, most of these haplogroups show comparable frequencies between the STA, LBKT and LBK,
N1a is the "signature group" of the LBK based on previous publications and now it seems that it was also found in the Starcevo culture of Hungary. The mtDNA PCA plot (right) shows clearly that the Hungarian farmers are very similar to the German ones so it seems that the LBK is a direct outgrowth of the Carpathian Neolithic; some earlier models of "demic diffusion" argued that Neolithic farmers spread slowly across Europe, picking up hunter-gatherer ancestry as they went along, but now it seems that at least in the Hungary->Germany part of this journey interaction with hunter-gatherers was minimum.

mtDNA change over time in Europe is pictured in Figure 3 (left) showing a shared haplotype analysis. The Y-chromosome data genetic distance is shown on the right and shows the Balkan-Anatolian-Caucasian-Mesopotamian relationship of the early farmer Y-chromosomes. Practically, this is due to haplogroup G2a (and especially G2a2b), which has turned up in lots of ancient European farmers (including the famous Iceman):
Three STA individuals belong to the NRY haplogroup F* (M89) and two specimens can be assigned to the G2a2b (S126) haplogroup, and one each to G2a (P15) and I2a1 (P37.2) (Dataset S3, S5). The two investigated LBKT samples carry haplogroups G2a2b (S126) and I1 (M253). Furthermore, the incomplete SNP profiles of eight specimens potentially belong to the same haplogroups; STA: three G2a2b (S126), two G2a (P15), and one I (M170); LBKT: one G2a2b (S126) and one F* (M89) (Dataset S5).
I believe this is the first ancient finding of haplogroup I1 which attains a peak in modern Swedes. This might be useful to those who have tied this to Germanic migrations because of this, as it was already in Central Europe with the earliest farmers.

Interestingly:
Surprisingly, Y chromosome haplogroups, such as E1b1b1 (M35), E1b1b1a1 (M78), E1b1b1b2a (M123), J2 (M172), J1 (M267), and R1b1a2 (M269), which were claimed to be associated with the Neolithic expansion [23–25], have not been found so far in the 6th millennium BC of the Carpathian Basin and Central Europe. Intriguingly, R1a and R1b, which represent the most frequent European Y chromosome haplogroups today, have been reported from cultures that emerged in Central Europe during the 3rd/2nd millennium BC, while a basal R type has been reported from a Palaeolithic sample in Siberia [60] in agreement with a proposed Central Asian/Siberian origin of this lineage. In contrast, G2a has not been detected yet in late Neolithic cultures [42,43]. This suggests further demographic events in later Neolithic or post-Neolithic periods.
A cautionary tale against over-reliance on modern distributions to trace ancient origins.

Also:
Considering the entire set of 32 published NRY records available for Neolithic Europe thus far, the low paternal diversity is indeed quite remarkable: G2a is the prevailing haplogroup in the Central European and Carpathian Basin Neolithic, and in French and Iberian Neolithic datasets [36,40,41]. There are only two exceptions, namely one E1b1b (V13) [41] individual from the Avellaner cave in Spain (~5,000-4,500 BC), and two I2a [40] individuals from Treilles, France (~3,000 BC).


biorxiv http://dx.doi.org/10.1101/008664

Tracing the genetic origin of Europe's first farmers reveals insights into their social organization

Anna Szécsényi-Nagy et al.

Farming was established in Central Europe by the Linearbandkeramik culture (LBK), a well-investigated archaeological horizon, which emerged in the Carpathian Basin, in today's Hungary. However, the genetic background of the LBK genesis has not been revealed yet. Here we present 9 Y chromosomal and 84 mitochondrial DNA profiles from Mesolithic, Neolithic Starčevo and LBK sites (7th/6th millennium BC) from the Carpathian Basin and south-eastern Europe. We detect genetic continuity of both maternal and paternal elements during the initial spread of agriculture, and confirm the substantial genetic impact of early farming south-eastern European and Carpathian Basin cultures on Central European populations of the 6th-4th millennium BC. Our comprehensive Y chromosomal and mitochondrial DNA population genetic analyses demonstrate a clear affinity of the early farmers to the modern Near East and Caucasus, tracing the expansion from that region through south-eastern Europe and the Carpathian Basin into Central Europe. Our results also reveal contrasting patterns for male and female genetic diversity in the European Neolithic, suggesting patrilineal descent system and patrilocal residential rules among the early farmers.

Link

June 21, 2013

Origins and dispersals of Y-chromosome haplogroup N

I will simply note that the authors use the effective mutation rate that is ~1/3 the genealogical mutation rate and hence their age estimates are inflated by ~3x. I have expressed reservations about using Y-STR based age estimates in general, but these concerns become more important for older lineages.

In particular, I would be very surprised if Y-haplogroup N turns up in Europe 8-10 thousand years ago, and I expect to see it make its first appearance in the 3rd millennium BC or thereabouts, perhaps together with the Seima-Turbino expansion across northern Eurasia. Thanks to the ancient DNA -preserving boreal cold, it may be possible to find out.

Irrespective of my disagreement on the mutation rate issue, I have to applaud the comprehensive survey carried out by these Chinese scientists: numbers invariably pay off.

PLoS ONE 8(6): e66102. doi:10.1371/journal.pone.0066102

Genetic Evidence of an East Asian Origin and Paleolithic Northward Migration of Y-chromosome Haplogroup N

Hong Shi et al.

The Y-chromosome haplogroup N-M231 (Hg N) is distributed widely in eastern and central Asia, Siberia, as well as in eastern and northern Europe. Previous studies suggested a counterclockwise prehistoric migration of Hg N from eastern Asia to eastern and northern Europe. However, the root of this Y chromosome lineage and its detailed dispersal pattern across eastern Asia are still unclear. We analyzed haplogroup profiles and phylogeographic patterns of 1,570 Hg N individuals from 20,826 males in 359 populations across Eurasia. We first genotyped 6,371 males from 169 populations in China and Cambodia, and generated data of 360 Hg N individuals, and then combined published data on 1,210 Hg N individuals from Japanese, Southeast Asian, Siberian, European and Central Asian populations. The results showed that the sub-haplogroups of Hg N have a distinct geographical distribution. The highest Y-STR diversity of the ancestral Hg N sub-haplogroups was observed in the southern part of mainland East Asia, and further phylogeographic analyses supports an origin of Hg N in southern China. Combined with previous data, we propose that the early northward dispersal of Hg N started from southern China about 21 thousand years ago (kya), expanding into northern China 12–18 kya, and reaching further north to Siberia about 12–14 kya before a population expansion and westward migration into Central Asia and eastern/northern Europe around 8.0–10.0 kya. This northward migration of Hg N likewise coincides with retreating ice sheets after the Last Glacial Maximum (22–18 kya) in mainland East Asia.

Link

September 22, 2011

Unexpected ancient mtDNA from Neolithic Hungary

This seems like a tie-in to another recent post on Neolithic and Bronze Age Ukraine. I don't think even a science fiction writer could have predicted the kinds of ancient DNA results we are getting from Europe. We have genetic discontinuity between Paleolithic and Neolithic, and between Neolithic and present, and, apparently, discontinuity between Neolithic cultures themselves, and wholly unexpected links to East Asia all the way to Central Europe.

When faced with data such as this, one can only say: what the hell happened during European prehistory?

UPDATE (8 Jun 2012): The age of these remains has been questioned.

Journal of Human Genetics advance online publication 15 September 2011; doi: 10.1038/jhg.2011.103

HVS-I polymorphism screening of ancient human mitochondrial DNA provides evidence for N9a discontinuity and East Asian haplogroups in the Neolithic Hungary

Zsuzsanna Guba et al.

Analysis of mitochondrial mutations in the HVS-I region is an effective method for ancient human populational studies. Discontinuous haplotype data between the first farmers and contemporary Europeans has been described before. Our contribution is based on a survey initiated on the Neolithic skeletons from Hungarian archaeological sites in the Alföld. This Lowland, the Hungarian Plain, is well excavated as an important region for spread of Neolithic culture from Near East and Balkans toward Central and Western Europe, started circa 8000 years ago. HVS-I sequences from nt15977 to nt16430 of 11 such specimens with sufficient mitochondrial DNA preservation among an extended Neolithic collection were analysed for polymorphisms, identifying 23 different ones. After assigning all single-nucleotide polymorphisms, a novel, N9a, N1a, C5, D1/G1a, M/R24 haplogroups were determined. On mitochondrial control mutations at nt16257 and nt16261, polymorphic PCRs were carried out to assess their distribution in remains. Neolithic data set was compared with contemporary Vác samples and references, resulting in higher frequency of N9a in Alföld as a remarkable genetic discontinuity. Our investigation is the first to study mutations form Neolithic of Hungary, resulting in an outcome of Far Eastern haplogroups in the Carpathian Basin. It is worth further investigation as a non-descendant theory, instead of a continuous population history, supporting genetic gaps between ancient and recent human populations.

Link

October 19, 2010

Origin of Neolithic N1a

My comments on this paper will be posted in this space; needless to say, I have serious objections to the idea that N1a is a Mesolithic European mtDNA.

UPDATE (Oct 20):

The paper makes a significant contribution to the phylogeny of N1a by full sequencing of mtDNAs belonging to individuals from different populations, ascribing the Neolithic sequences to several identified clades. That part of the paper is solid and interesting.

My main problems with the paper are threefold:

1. The paper attempts to infer the origin of mtDNA founders using TMRCA estimates. But, as I have pointed out, TMRCAs of clades tell us nothing about where the common ancestors lived. The TMRCA of Latin American R1b, for example, predates the arrival of Western Europeans into the Americas by thousands of years.

2. The paper attempts to infer the origin of mtDNA founders using modern populations. Given the clear evidence for discontinuity between the Mesolithic and Neolithic and present in Central Europe, due to either demography or selection, I find it a very questionable proposition. If N1a turns up in dated human remains associated with a Mesolithic culture of Europe prior to the arrival of the Neolithic economy, then the hypothesis that it is a forager lineage is unsubstantiated.

3. Finally, the paper uses the frequency of identified subclades to infer the location of the founders. In addition to the above 2 criticisms, I must point out that this puts the cart before the horse. In a uniform landscape, we do expect present-day frequency to be related to the place of origin of a mutation. But, we are not dealing with such a landscape. In particular, we are dealing with an expanding population exploiting new territory. As an analogy, the few people who made the crossing into the Americas left a few relatives in the Old World, and produced a plethora of new ones (descendants) in the New World. They did so by exploiting their new environment.

An additional objection, is, of course, that the idea of Mesolithic N1a in Europe requires a virtual partition of pre-Neolithic European populations, to account for its non-existence among north/central Mesolithic North/Central Europeans. That is hard to swallow, unless by "Mesolithic" one means "very shortly before the Neolithic", which would make it possible for a lineage to establish itself in e.g., the Balkans shortly prior to the onset of the Neolithic, and begin expanding shortly thereafter. However, I don't see how an argument could be made for such a scenario, and, of course, I doubt that genetic dating methods in modern populations have enough precision to allow one to distinguish between late Mesolithic and early Neolithic intrusions.


BMC Evolutionary Biology 2010, 10:304doi:10.1186/1471-2148-10-304

Mitochondrial haplogroup N1a phylogeography, with implication to the origin of European farmers

Malliya GOUNDER Palanichamy et al.

Background
Tracing the genetic origin of central European farmer N1a lineages can provide a unique opportunity to assess the patterns of the farming technology spread into central Europe in the human prehistory. Here, we have chosen twelve N1a samples from modern populations which are most similar with the farmer N1a types and performed the complete mitochondrial DNA genome sequencing analysis. To assess the genetic and phylogeographic relationship, we performed a detailed survey of modern published N1a types from Eurasian and African populations.

Results
The geographic origin and expansion of farmer lineages related N1a subclades have been deduced from combined analysis of 19 complete sequences with 166 N1a haplotypes. The phylogeographic analysis revealed that the central European farmer lineages have originated from different sources: from eastern Europe, local central Europe, and from the Near East via southern Europe.

Conclusions
The results obtained emphasize that the arrival of central European farmer lineages did not occur via a single demic diffusion event from the Near East at the onset of the Neolithic spread of agriculture into Europe. Indeed these results indicate that the Neolithic transition process was more complex in central Europe and possibly the farmer N1a lineages were a result of a 'leapfrog' colonization process.

Link

August 18, 2010

Ancient Megalithic mtDNA from France

An extremely interesting paper, the first one on Megalithic remains, and a link between the Megalithic people and the early central European Neolithic Linearbandkeramik, where N1a was unexpectedly detected as a major component a few years ago. I'll probably have more to say on this after I read the paper.

UPDATE:

From the paper:
We reproducibly retrieved partial HVR-I sequences (nps 16,165 to 16,390) from three human remains (Prisse´ 1, 2, and 4, Table 1), one adult and two children deposited during different stages of use of the burial chamber. Corresponding sequences could be unambiguously assigned to haplogroups X2, U5b, and N1a (Table 2 and Supporting Online Information).
Haplogroup U5b subclusters are believed to have spread from central-southern Europe post-LGM. Haplogroup X2 is believed to have spread from the Near East and Mediterranean Europe; it is one of those mystery haplogroups that turn up in the Taklamakan desert as well as Native Americans. Together with the clearly invasive nature of N1a, these results are consistent with migrationism.

The authors write:
The widespread distribution of the N1a lineage in Early and Middle Neolithic northwestern Europe may indicate genetic continuity from Mesolithic populations.
This scenario would support a Mesolithic contribution to the earliest Neolithic of Atlantic Europe. This would imply that the N1a lineage was already common in
indigenous north European populations and that the spread of the Neolithic was principally the result of cultural diffusion. Although so far the N1a lineage has not
been encountered among late European hunter-gatherers in central and north Europe (Bramanti et al., 2009; Malmstro¨m et al., 2009), it is worth noting that less
than half of the hunter-gatherers’ paleogenetic data come indeed from the pre-Neolithic period (predating LBK expansion). Finally, no paleogenetic data currently
exist for the Mesolithic period in Western Europe. This prevents any conclusion being drawn about N1a occurrence during the Mesolithic period in those regions.
Of course we won't know if N1a occurred in France prior to the Neolithic until we test pre-Neolithic French samples. However, if N1a was present in France prior to the Neolithic, then why wasn't it present in central-northern Europe where substantial sample sizes exist? This would require a partition of pre-Neolithic populations of Europe, and also existence of N1a in both the Linearbandkeramik (that spread on a south-north vector) and in Mesolithic French. So, while we wait for pre-Neolithic Western Europeans to come up N1a, I'm willing to wager that they will not, and that N1a spread into France with the Neolithic or the later spread of Megalithic cultures.

Related:

American Journal of Physical Anthropology DOI: 10.1002/ajpa.21376

News from the west: Ancient DNA from a French megalithic burial chamber

Marie-France Deguilloux et al.

Recent paleogenetic studies have confirmed that the spread of the Neolithic across Europe was neither genetically nor geographically uniform. To extend existing knowledge of the mitochondrial European Neolithic gene pool, we examined six samples of human skeletal material from a French megalithic long mound (c.4200 cal BC). We retrieved HVR-I sequences from three individuals and demonstrated that in the Neolithic period the mtDNA haplogroup N1a, previously only known in central Europe, was as widely distributed as western France. Alternative scenarios are discussed in seeking to explain this result, including Mesolithic ancestry, Neolithic demic diffusion, and long-distance matrimonial exchanges. In light of the limited Neolithic ancient DNA (aDNA) data currently available, we observe that all three scenarios appear equally consistent with paleogenetic and archaeological data. In consequence, we advocate caution in interpreting aDNA in the context of the Neolithic transition in Europe. Nevertheless, our results strengthen conclusions demonstrating genetic discontinuity between modern and ancient Europeans whether through migration, demographic or selection processes, or social practices.

Link

July 31, 2010

Ancient Nordic mtDNA (Melchior et al. 2010)

The reduction of mtDNA haplogroup I in modern Scandinavians has been observed before (by the same author). Inferences from the 2 Bell Beaker and 1 Bronze Age samples which belong to U subgroups should be cautious, however these contrast with later groups as well as with the earlier Neolithic Scandinavian TRB samples. Table 5 has haplogroup frequencies in various age-place groups. From the paper:

Table 5 shows the occurrence of haplogroups among ancient Danes and Britons and modern Danes and Scandinavians. Using G-tests, no significant deviations were observed among the extant populations or between the ancient Britons and the ancient Danes, despite the two ancient population samples show a surplus of Hg T and Hg I, respectively. We have previously observed a high frequency of Hg I's among Iron Age villagers (Bøgebjerggård) and individuals from the early Christian cemetery, Kongemarken [16], [17]. This trend was also found for the additional sites reported here, Simonsborg, Galgedil and Riisby. The overall frequency of Hg I among the individuals from the Iron Age to the Medieval Age is 13% (7/53) compared to 2.5% for modern Danes [35]. The higher frequencies of Hg I can not be ascribed to maternal kinship, since only two individuals share the same common motif (K2 and K7 at Kongemarken). Except for Skovgaarde (no Hg I's observed) frequencies range between 9% and 29% and there seems to be no trend in relation to time.
There are two main explanations for the reduction in haplogroup I frequency: (a) negative selection and/or (b) the movement of non-I bearing populations into the region of interest. Unless selection occurred very recently (in the last millennium), the lack of a temporal trend adds some weight in favor of (b) and contra (a).

Of interest:
Several haplogroups which are rare or absent among the extant population of southern Scandinavia were observed. Hg's R0a and U7 have been discussed previously [15], [17]. Here we note the finding of Hg N1a in the Medieval Riisby (Table 3), which seems to be common among early European LBK farmers [10], a rare Hg T2 motif in the Iron Age settlement Simonsborg (Table 2) and Hg U5a and Hg U4 at the Early Bronze Age site Bredtoftegård and Neolithic Damsbo (Table 1).
A recent paper on mtDNA haplogroup R0a.

A main conclusion from this paper is that the mtDNA gene pool does not appear to change "monotonically" with time, as the Neolithic Bell Beaker and Bronze Age groups resemble Mesolithic ones rather than the Neolithic TRB. Thus, it is safe to say that simple one-time admixture scenaria between "Paleolithic" and "Neolithic" gene pools grossly oversimplify reality.

The more we learn about prehistory, the less we can believe in the paradigm of static people changing their subsistence, technology, language from the Paleolithic to the present. Migrationism is overdue for a comeback as an explanatory tool for the plethora of unexpected results that the bones of ancient humans present us with.

The persistence of mtDNA-U gene pools down to the Bronze Age leads the authors to consider the Iron Age as the origin of the modern Scandinavian mtDNA gene pool:
However, the frequency of Hg U4 and U5 declines significantly among our more recent Iron Age and Viking Age Danish population samples to the level observed among the extant Danish population. Our study therefore would point to the Early Iron Age and not the Neolithic Funnel Beaker Culture as suggested by Malmström et al. (2009) [14], as the time period when the mtDNA haplogroup frequency pattern, which is characteristic to the presently living population of Southern Scandinavia, emerged and remained by and large unaltered by the subsequent effects of genetic drift.
I find that a reasonable suggestion, as it was in the Iron Age that the Germanic language group seems to have emerged in southern Scandinavia and northern Germany, and started to experience its demographic expansion that rendered it one of the largest in modern Europe. So, it makes sense that the mtDNA composition of that age would persist down to the present-day inhabitants.

Related:
PLoS ONE 5(7): e11898. doi:10.1371/journal.pone.0011898

Genetic Diversity among Ancient Nordic Populations

Linea Melchior et al.

Using established criteria for work with fossil DNA we have analysed mitochondrial DNA from 92 individuals from 18 locations in Denmark ranging in time from the Mesolithic to the Medieval Age. Unequivocal assignment of mtDNA haplotypes was possible for 56 of the ancient individuals; however, the success rate varied substantially between sites; the highest rates were obtained with untouched, freshly excavated material, whereas heavy handling, archeological preservation and storage for many years influenced the ability to obtain authentic endogenic DNA. While the nucleotide diversity at two locations was similar to that among extant Danes, the diversity at four sites was considerably higher. This supports previous observations for ancient Britons. The overall occurrence of haplogroups did not deviate from extant Scandinavians, however, haplogroup I was significantly more frequent among the ancient Danes (average 13%) than among extant Danes and Scandinavians (~2.5%) as well as among other ancient population samples reported. Haplogroup I could therefore have been an ancient Southern Scandinavian type “diluted” by later immigration events. Interestingly, the two Neolithic samples (4,200 YBP, Bell Beaker culture) that were typed were haplogroup U4 and U5a, respectively, and the single Bronze Age sample (3,300–3,500 YBP) was haplogroup U4. These two haplogroups have been associated with the Mesolithic populations of Central and Northern Europe. Therefore, at least for Southern Scandinavia, our findings do not support a possible replacement of a haplogroup U dominated hunter-gatherer population by a more haplogroup diverse Neolithic Culture.

Link

February 07, 2010

mtDNA of Cres Islanders

Coll Antropol. 2009 Dec;33(4):1323-8.

Mitochondrial DNA heritage of Cres Islanders--example of Croatian genetic outliers.

Jeran N, Havas Augustin D, Grahovac B, Kapović M, Metspalu E, Villems R, Rudan P.

Diversity of mitochondrial DNA (mtDNA) lineages of the Island of Cres was determined by high-resolution phylogenetic analysis on a sample of 119 adult unrelated individuals from eight settlements. The composition of mtDNA pool of this Island population is in contrast with other Croatian and European populations. The analysis revealed the highest frequency of haplogroup U (29.4%) with the predominance of one single lineage of subhaplogroup U2e (20.2%). Haplogroup H is the second most prevalent one with only 27.7%. Other very interesting features of contemporary Island population are extremely low frequency of haplogroup J (only 0.84%), and much higher frequency of haplogroup W (12.6%) comparing to other Croatian and European populations. Especially interesting finding is a strikingly higher frequency of haplogroup N1a (9.24%) presented with African/south Asian branch almost absent in Europeans, while its European sister-branch, proved to be highly prevalent among Neolithic farmers, is present in contemporary Europeans with only 0.2%. Haplotype analysis revealed that only five mtDNA lineages account for almost 50% of maternal genetic heritage of this island and they present supposed founder lineages. All presented findings confirm that genetic drift, especially founder effect, has played significant role in shaping genetic composition of the isolated population of the Island of Cres. Due to presented data contemporary population of Cres Island can be considered as genetic "outlier" among Croatian populations.

Link

September 30, 2009

Some mtDNA links between Europe and Asia

I was planning on writing up a more complete narrative for this post, but I don't think the evidence is -as of yet- strong enough to support very strong speculation. I will simply say that the recent results of Bramanti et al. for a U-dominated older mtDNA stratum in Central/North-eastern Europe can be reasonably extended to cover both North-western Europe and northern Eurasia up to Lake Baikal, the prehistoric limit between Caucasoids and Mongoloids.

This boreal zone of U dominance contrasts with that of the Neolithic and Bronze Age inhabitants, where the familiar mix of ten or so main Caucasoid haplogroups makes its appearance, in various proportions and in various degrees of admixture at the eastern end of its expansion. The eastern Caucasoids were probably derived from both (i) West Asia via the spread of the Neolithic economy to the east wherever it could be ecologically supported, (ii) in the more northern parts, from migrations across the steppe from Central and Eastern Europe.

More ancient DNA research is needed to establish (i) how complete was the U dominance in the pre-Neolithic northern zone, and (ii) when, and where did the other Caucasoid haplogroups break into it.

Anyway, here is the post as it stands:

Ricaut et al. (2004) discovered the presence of mtDNA haplogroup N1a (16147A, 16172C, 16223T, 16248T, and 16355T) in an Iron Age Scytho-Siberian skeleton from the Altai, reporting the presence of haplogroup N1a among Iranians and upper caste Havik Brahmins from India.

The same sequence was detected in a Neolithic Central European (DER1) of the Linearbandkeramik (LBK) culture, with reported modern matches in Egypt and Armenia. The following haplogroups were detected in the Neolithic LBK gene pool: H*, N1a, K, HV, T2, V, J, W, U3.

A later study by Gokcumen et al. (2008) discovered the presence of N1a in modern Kazakhs from the Altai:
The haplotypic variation within the seven N1a samples was relatively high (Table 2), with these haplotypes belonging to both the European and Central Asian branches of this haplogroup, as recently defined by Haak et al. (2005). Thus, the source of N1a haplotypes in Altaian Kazakhs was unclear, although they seemed to have originated west of this part of Central Asia (Gokcumen et al., 2007).
Haplogroup N1a was found to be a genuine signature of the Central European Neolithic by contrasting its high representation in the LBK with the overwhelming presence of haplogroup U (and especially U5 and U4) mtDNA among the Paleolithic and Mesolithic populations of the region.

A separate Neolithic Funnel Beaker (TRB) sample from Scandinavia (Malmström et al. 2009) included only three individuals belonging to haplogroups H, J, and T. Obviously, a sample of 3 is insufficient, but the absence of haplogroup U in it parallels that of the LBK. By contrast, the contemporaneous Mesolithic Pitted Ware culture, represented by 19 samples had single instances of J, and T (which may be due to admixture with the TRB), a single instance of haplogroup V, one of the few ones thought to be European in origin, and a gene pool that was apparently dominated by haplogroups U4 and U5. The picture emerging from the northmost European hunter-gatherers is one of a restricted set of haplogroups where U subclades were dominant (about 3/4).

N1a was also detected in medieval high-status Hungarians:
Commoners show a predominance of mtDNA haplotypes and haplogroups (H, R, T), common in west Eurasia, while high-status individuals, presumably conquering Hungarians, show a more heterogeneous haplogroup distribution, with haplogroups (N1a, X) which are present at very low frequencies in modern worldwide populations and are absent in recent Hungarian and Sekler populations.
While, as we saw, N1a was frequent among Neolithic Central Europeans, its absence in Hungarian commoners suggests that it was re-introduced -in the high status individuals- from Asia.

Interestingly, there has been European and Asian mtDNA evidence that allows us to have a good idea of the mtDNA landscape on which N1a-bearing people migrated from west to east:

The pre-farming foragers of Europe were dominated by mtDNA haplogroup U. The easternmost sample in the aforementioned study was from Samara, in European Russia and consisted of a U5a, and a U5a1 sample. How far to the west and east did the U-dominated population of pre-Neolithic northern Caucasoids extend?

Neolithic Siberians from Lake Baikal, the eastermost anthropologically attested limit of prehistoric Caucasoid populations had only U5a as a Western Caucasoid element in a population dominated by Eastern Eurasian mtDNA. Similarly, the Lokomotiv Siberian burials from Lake Baikal only had U5a in an other Mongoloid mtDNA gene pool. Yu Hong, a Sogdian in China (1,400 years ago) also belonged to haplogroup U5.

U5a was not limited to the territory of Central Europe to China in ancient times. It was the haplogroup of Cheddar Man, a Paleolithic Briton, and U5a1 or U5a1a has also been detected in a Mycenaean from Bronze Age Greece. Interestingly, U5a1 seems to have decreased in frequency in Britain from the 4th c. to the present.

Is it possible that negative selection is affecting mtDNA frequencies in Europe? U-haplogroup turns up in many ancient DNA samples, but the discovery that it was absent (or non-detectible) in Neolithic farmers raises the possibility that its reduced frequency may be due to demography, i.e., the overwhelming of Paleolithic foragers by Neolithic (and later) intruders.

We know that in the Bronze and subsequent ages, Siberians from Krasnoyarsk belonged to a rich assortment of Caucasoid haplogroups. It seems that newcomers from the West joined the U-dominated earliest settlers:
Twenty samples were found to belong to west Eurasian haplogroups (U2, U4,
U5a1, T1, T3, T4, H5a, H6, HV, K, and I
), whereas the 6 remaining samples were attributed to east Eurasian haplogroups (Z, G2a, C, F1b and N9a).
At the other end of the Eurasiatic steppe, in the Bronze Age site of Eulau in Germany, the gene pool was also quite different from that of the Paleolithic inhabitants, with haplogroups K1b, U5b, I, H, X2, K1a2 detected.

Haplogroup X2 represents another link between the west and Siberia according to Reidla et al. (2003):
Overall, it appears that the populations of the Near East, the Caucasus, and Mediterranean Europe harbor subhaplogroup X2 at higher frequencies than those of northern and northeastern Europe (P less than .05) and that X2 is rare in Eastern European as well as Central Asian, Siberian, and Indian populations and is virtually absent in the Finno-Ugric and Turkic-speaking people of the Volga-Ural region. [...] the few Altaian (Derenko et al. 2001) and Siberian haplogroup X lineages are not related to the Native American cluster, and they are more likely explained by recent gene flow from Europe or from West Asia.
The Tubalar, Altaic speakers from the northeastern Altai showed a mixed Caucasoid-Mongoloid mtDNA gene pool, with the western component consisting of haplogroups H8, U4b, U5a1, and X2e:
Specifically, northeastern Altai appears to be a good candidate for the ancestral homeland of the haplogroup U4b, which is apparently ancient European. For some haplogroups, such as X2e, the relatively recent arrival to the Altai region is more likely.
Derenko et al. (2002) discovered a rich assortment of Caucasoid haplogroups in several populations from the Altai, including all aforementioned ones (H, HV1, J*, J1, J1b1, T1, T4, U1a, U2, U3, U4, U5a1, I, X and N1a):
The applied approach permitted identification of 60% of mtDNA types the majority of which had southern Caucasoid origin. Less than 10% of mtDNA types were of eastern European origin.
Derenko et al. (2003) also studied several populations from South Siberia where the Caucasoid component was much diminished (17%) with the following haplogroups present: H, U, J, T, I, N1a, X.

September 03, 2009

Central European farmers not descended from local hunter-gatherers (Bramanti et al. 2009)

This is the real power of DNA: the topic of whether central European farmers were the result of demic diffusion from the southeast or indigenous hunter-gatherers who adopted the agricultural economy has been endlessly debated in archaeological circles.

We are finally in a position to give an answer to the question, and the answer is in favor of the diffusionist camp and against the idea of acculturation by local hunter-gatherers. Surprisingly, modern Central Europeans do not appear to be a simple hunter-gatherer/farmer mix, suggesting that even later events (post-Neolithic) have shaped their genetic diversity.

This study is also a powerful argument against the idea of genetic continuity across long time spans. Most ancient DNA studies so far have reached a similar conclusion. Thus, it also destroys the supposed justification for continuity from Paleolithic Europe to modern times that early mtDNA work (of the Daughters of Eve variety) has proposed, hand in hand with the hunter acculturation hypothesis.

The paper is covered in National Geographic:
Central and western Europe's first farmers weren't crafty, native hunter-gatherers who gradually gave up their spears for seeds, a new study says.

Instead, they were experienced outsiders who arrived on the scene around 5500 B.C. with animals in tow—and the locals apparently didn't roll out the welcome wagon.

"Within a few generations, all the farmers—probably coming from southeast Europe—moved into central Europe bringing their culture, [livestock], and everything," Joachim Burger, a molecular archaeologist at the University of Mainz in Germany, said via email.

The finding is based on analysis of genetic material in the skeletal remains of ancient hunter-gatherers and early farmers found in Germany, Lithuania, Poland, and Russia—though farming is thought to have reached areas as far west as western France during the period of rapid expansion, about 7,500 years ago.

The study goes against a long-standing idea that Europe's first farmers were former hunter-gatherer populations that had settled the region after the last ice age, about 10,000 years ago.

Perhaps, the thinking went, the hunter-gatherers had observed farming practices during their travels or had learned from neighbors.

Instead, the researchers found, the hunter-gatherers and the early farmers remained segregated, according to the study, to be published tomorrow in the journal Science.
And the press release:
Analysis of ancient DNA from skeletons suggests that Europe's first farmers were not the descendants of the people who settled the area after the retreat of the ice sheets. Instead, the early farmers probably migrated into major areas of central and eastern Europe about 7,500 years ago, bringing domesticated plants and animals with them, says Barbara Bramanti from Mainz University in Germany and colleagues. The researchers analyzed DNA from hunter-gatherer and early farmer burials, and compared those to each other and to the DNA of modern Europeans. They conclude that there is little evidence of a direct genetic link between the hunter-gatherers and the early farmers, and 82 percent of the types of mtDNA found in the hunter-gatherers are relatively rare in central Europeans today.

For more than a century archaeologists, anthropologists, linguists, and more recently, geneticists, have argued about who the ancestors of Europeans living today were. We know that people lived in Europe before and after the last big ice age and managed to survive by hunting and gathering. We also know that farming spread into Europe from the Near East over the last 9,000 years, thereby increasing the amount of food that can be produced by as much as 100-fold. But the extent to which modern Europeans are descended from either of those two groups has eluded scientists despite many attempts to answer this question.

Now, a team from Mainz University in Germany, together with researchers from UCL (University College London) and Cambridge, have found that the first farmers in central and northern Europe could not have been the descendents of the hunter-gatherers that came before them. But what is even more surprising, they also found that modern Europeans couldn't solely be the descendents of either the hunter-gatherer alone, or the first farmers alone, and are unlikely to be a mixture of just those two groups. "This is really odd", said Professor Mark Thomas, a population geneticist at UCL and co-author of the study. "For more than a century the debate has centered around how much we are the descendents of European hunter-gatherers and how much we are the descendents of Europe's early farmers. For the first time we are now able to directly compare the genes of these Stone Age Europeans, and what we find is that some DNA types just aren't there - despite being common in Europeans today."

Humans arrived in Europe 45,000 years ago and replaced the Neandertals. From that period on, European hunter-gatherers experienced lots of climatic changes, including the last Ice Age. After the end of the Ice Age, some 11,000 years ago, the hunter-gatherer lifestyle survived for a couple of thousand years but was then gradually replaced by agriculture. The question was whether this change in lifestyle from hunter-gatherer to farmer was brought to Europe by new people, or whether only the idea of farming spread. The new results from the Mainz-led team seems to solve much of this long standing debate.

"Our analysis shows that there is no direct continuity between hunter-gatherers and farmers in Central Europe," says Prof Joachim Burger. "As the hunter-gatherers were there first, the farmers must have immigrated into the area."

The study identifies the Carpathian Basin as the origin for early Central European farmers. "It seems that farmers of the Linearbandkeramik culture immigrated from what is modern day Hungary around 7,500 years ago into Central Europe, initially without mixing with local hunter gatherers," says Barbara Bramanti, first author of the study. "This is surprising, because there were cultural contacts between the locals and the immigrants, but, it appears, no genetic exchange of women."

The new study confirms what Joachim Burger´s team showed in 2005; that the first farmers were not the direct ancestors of modern European. Burger says "We are still searching for those remaining components of modern European ancestry. European hunter-gatherers and early farmers alone are not enough. But new ancient DNA data from later periods in European prehistory may shed also light on this in the future."
And from archaeology.about.com:
A new study published by Barbara Bramanti and colleagues in Science Express on September 4, 2009, supports what some scholars have suspected all along—that the LBK likely were an in-migration of people from the Balkans, and that they did not, initially anyway, do much mixing at all with the earlier inhabitants of Europe.

Bramanti and her colleagues compared the mitochondrial DNA from 20 central European Upper Paleolithic, Mesolithic and Neolithic hunter-gatherers to that from 25 Neolithic farmers and 484 modern Europeans, spanning an age range from about 13,400 to 2,300 BC. The data shows that the early farmers and hunter-gatherers were from distinctively different populations.

This paper follows up on and to a degree contradicts with the hypothesis of an earlier paper that looked only at mtDA of the Neolithic farmers. That study (Haak et al. 2005) discovered that the farmers had a distinctive difference between the current residents of Europe, and hypothesized that that meant that the hunter-gatherers might have been more like the modern inhabitants, and thus, the LBK would have been only a minor component.
The earlier paper by Haak et al. they refer to.

(More technical details once I read the full paper)

UPDATE:

Pre-farming populations seem to have been dominated by mtDNA haplogroup U:
it is intriguing to note that 82% of our 22 hunter-gatherer individuals carried clade U (fourteen U5, two U4, and two unspecified U-types; table 1).
The hunter-gatherers had no N1a -which was a signature of early farmers in the Haak et al. paper- or of haplogroup H, the most common mtDNA haplogroup in Europeans today. The only non-U types in hunter-gatherers were all from the Ostorf site and included haplogroups T2e, J, and K.

The farmers:
In a previous study, we showed that the early farmers of Central Europe carried mainly N1a, but also H, HV, J, K, T, V, and U3 types (11, 12). We found no U5 or U4 types in that early farmer sample.
UPDATE I:

It is important to note the implications of this study: the most certain conclusion is that Neolithic farmers in Central Europe are very sharply differentiated from the Paleolithic-Mesolithic populations. This is clear evidence in favor of the diffusionist idea, since the acculturation hypothesis predicts that the mtDNA of the early farmers would be roughly that of the pre-farming population that picked up the new technology.

However, the evidence of this paper also contradicts the plain demic diffusion hypothesis. According to this hypothesis, farmer genes are gradually replaced by hunter genes as the farming economy spreads, because in each step there is a mix of farmer-indigenous populations which go on to colonize regions beyond the frontier. This is not what appears to have happened. Rather, it seems the farmers moved across Europe with very little interaction with pre-farmers. A long period of no contact between the LBK and foragers is actually supported by archaeology. I have termed this type of diffusion the "skipping stone":
In the Skipping Stone model, farmers move out in search of new territories before they have started to blend with the local foragers; the genetic impact of the initiators of the movement is preserved.
The great speed of the Linearbandkeramik farmers was also experienced by farmers who spread across the Mediterranean. The spread of agriculture in Europe does not appear to have been a slow process of interaction between farmer and forager, but rather a blitz by the first farmers, followed later, after the spread had already occurred by admixture with some of the foragers that remained.

We must also be certain not to jump into conclusions about the relative contributions of farmer and forager in the modern gene pool. Clearly both the idea of a predominantly "Paleolithic" and a predominantly "Neolithic" gene pool is problematic; such continuity is not really evident. However, the reasons for the discontinuity up to the present may be manifold: e.g., later population movements into Europe, or natural selection changing the gene pool without subsequent change of population.

What we do know is this: first farmers were not local foragers who abandoned the old ways for the new ones. Amalgamation between farmer and forager did not happen quickly as the farming economy spread. Finally it did happen, of course, and either because (i) there were few foragers in the mix, or (ii) their mtDNA was selected against, modern central Europeans have very little mitochondrial descent from the earliest European populations.

PS: Natural selection against forager mtDNA is not very outlandish. For example, a severe reduction of U5a1 and U5b haplogroup in Britain from ancient to modern times has been observed, which could potentially mark another data point in a process of selection against that haplogroup over time.

My personal guess is that both demography and selection may have played a role in the marginalization of hunter-gatherer mtDNA . LBK farmers were already 3 thousand years removed from the earliest agriculturalists of the Near East, so it is conceivable that they had evolved an mtDNA gene pool adapted to the new lifestyle that outcompeted the indigenous European one. But, the long period of isolation from foragers may mean that only farmer mtDNA benefited from the demographic boom associated with the new economy, and by the time relations between the two groups warmed up, the relatively few newcomers already dwarfed the older population demographically.

UPDATE II (Sep 4):

To understand the magnitude of the difference between farmers and hunter-gatherers, the authors calculate their Fst=0.163, which can be compared with a maximum value of 0.0327 among modern Europeans and 0.133 for modern Eurasians from Europe to Australia. Subsequently, the authors test the hypotheses of (a) continuity between hunter-gatherers and farmers, and (b) continuity between hunter-gatherers and modern Central Europeans, rejecting both.

This isn't very surprising in the light of the anthropological evidence in favor of diffusion of farmers from the Near East and against the acculturation hypothesis presented recently by Pinhasi et al. The very close relationship of the LBK skulls and their proximity to samples from Nea Nikomedeia in Greece and Catal Hoyuk in Anatolia contrasts with the Mesolithic populations.

UPDATE III (Sep 21):

Some possible anthropological evidence for post-LBK infusion into Central Europe:
Mesolithic Europeans display considerable variation in humero-clavicular and brachial indices yet none approach the extreme "hyper-polar" morphology of LBK humans from the MESV. In contrast, Late Neolithic and Early Bronze Age peoples display elongated brachial and crural indices reminiscent of terminal Pleistocene and "tropically adapted" recent humans. These marked morphological changes likely reflect exogenous immigration during the terminal Fourth millennium cal BC.

Science doi:10.1126/science.1176869

Genetic Discontinuity Between Local Hunter-Gatherers and Central Europe’s First Farmers

B. Bramanti et al.

Following the domestication of animals and crops in the Near East some 11,000 years ago, farming reached much of Central Europe by 7,500 years before present. The extent to which these early European farmers were immigrants, or descendants of resident hunter-gatherers who had adopted farming, has been widely debated. We compare new mitochondrial DNA (mtDNA) sequences from late European hunter-gatherer skeletons with those from early farmers, and from modern Europeans. We find large genetic differences between all three groups that cannot be explained by population continuity alone. Most (82%) of the ancient hunter-gatherers share mtDNA types that are relatively rare in Central Europeans today. Together, these analyses provide persuasive evidence that the first farmers were not the descendants of local hunter-gatherers but immigrated into Central Europe at the onset of the Neolithic.

Link

July 02, 2009

Genetic discontinuities between Etruscans and modern Tuscans

It is great that such a large medieval sample was assembled for this study, and hopefully it will be possible to type it for either Y chromosome or autosomal markers to determine whether continuity between medieval and modern Tuscans was only matrilineal.

I am not very surprised by the inferred genetic discontinuity. Gene pools maintain their separateness if their bearers have some sort of distinction (linguistic, political, religious, or cultural) from their neighbors. For Etruscans, such distinctions were rapidly dissolved when they were annexed by the Romans. In Imperial times, their language was still known by some, but this, too, passed into oblivion.

As distinctions disappear, so do impediments to bidirectional gene flow. The genetic characteristics of the original people do not so much disappear (genetic genealogists will surely soon scour the databases for ancient Etruscan matches, if they haven't done it already), but are diffused in the larger pool of now undifferentiated neighbors, who, in their turn, diffuse into the territory of the old ethnic entity.

The "Etruscans" label of this post points to many studies in this unfolding story of Etruscan origins. Etruscans remain, until now, the only ancient Mediterranean population for which a substantial mtDNA characterization exists.

PS: Interestingly, the conference abstract which I pointed to earlier seemed to suggest that the genetic discontinuity occurred after 1,500AD rather than before 1,000AD, as the published paper does.

(More on the details of the study to follow after I read the paper)

UPDATE I (Jul 2)

From my reading of Table 2, the medieval Tuscan sequences are:

10 of CRS
2 of 16311C
2 of 16294T 16296T 16304C

and 1 of the following:

16224C 16311C 16355T
16274A
16126C 16193T
16126C 16193T 16294T 16296T 16304C
16114A
16174T
16304C
16318T
16126C 16294T 16296T 16304C
16223T
16189C
16261T
16126C

which seems to indicate a mix of haplogroups H, HV, T, and K in the population according to the Genographic project tool.

UPDATE II (Jul 2)

From the paper:
Analyses of mtDNA diversity in the British Isles (Töpf et al. 2007), and Iceland (Helgason et al. 2009), also showed sharp differences between historical and current populations. In addition, a large fraction (up to 80%, depending on the region considered) of the Dutch surnames were displaced from the areas in which their frequency was highest three centuries ago (Manni et al. 2005). Nobody can tell whether the Netherlands represent an exception or the rule, until similar studies are carried out elsewhere, and there is no comparable information on previous centuries. However, the point here is that a genetic discontinuity between present and past populations seems rather common in the few European countries studied so far. Deep demographic changes in the last two millennia are both suggested by the analysis of ancient DNA in Tuscany, Iceland and Britain, and empirically demonstrated in the Netherlands. Our failure to reproduce by simulation the observed haplotype number of the contemporary Tuscan samples may mean that such changes involved multiple immigration processes, too complex to model at present.
The paper by Töpf et al. in turn points to this study of ancient British mtDNA which I had forgotten about. That study shows an increase of haplogroup H (as most of the OTHER probably is) in modern times compared to the past, and the drastic reduction of some haplogroups as U5a1 and U5a1a. Other cases of apparent drastic change over time, involves the Central Europeans (reduced haplogroup N1a) compared to early Central European farmers., and medieval vs. modern Danes (reduced haplogroup I).

So, the picture does seem to suggest substantial changes in mtDNA gene pools over time across many parts of Europe and time frames. Whether this reflects population movements or selection, remains to be seen. In the paper on the Netherlands, for examples (Manni et al.) cited in this paper shows that the original surnames in a region can be rapidly replaced over a genealogical time frame.

Studies such as these put into question the widely held assumption that modern gene pools reflect prehistorical events, such as the repopulation of Europe after the glacial age, or the advent of farming. If genetic change is so substantial over 100 generations, we are rather foolish, I believe, to attempt prehistoric reconstructions about events that took place 300 or even 600 generations ago.

UPDATE (July 13): An additional factor that may explain why ancient gene pools look different than modern ones may be of course due to post-mortem damage of the DNA, which makes it look different when it is not so. However, in the case of the Etruscan data of Vernesi et al., the question of DNA degradation was addressed in an independent study by Mateiu et al. which found no evidence for it.

Thus, while one can't be too cautious, the evidence seems strong in this case that we are dealing with an authentic snapshot of ancient Etruscan mtDNA.

Molecular Biology and Evolution, doi:10.1093/molbev/msp126

Genealogical discontinuities among Etruscan, Medieval and contemporary Tuscans

Silvia Guimaraes et al.

The available mitochondrial DNA (mtDNA) data do not point to clear genetic relationships between current Tuscans and the Bronze-Age inhabitants of Tuscany, the Etruscans. To understand how and when such a genetic discontinuity may have arisen, we extracted and typed the mtDNAs of 27 medieval Tuscans from an initial sample of 61, spanning a period between the 10th and 15th centuries A.D.. We then tested by serial coalescent simulation various models describing the genealogical relationships among past and current inhabitants of Tuscany, the latter including three samples (from Murlo, Volterra, Casentino) which were recently claimed to be of Etruscan descent. Etruscans and medieval Tuscans share three mitochondrial haplotypes, but fall in distinct branches of the mitochondrial genealogy in the only model that proved compatible with the data. Under that model, contemporary people of Tuscany show clear genetic relationships with Medieval people, but not with the Etruscans, along the female lines. No evidence of excess mutation was found in the Etruscan DNAs by a Bayesian test, and so there is no reason to suspect that these results be biased by systematic contamination of the ancient sequences or laboratory artefacts. Extensive demographic changes before 1000 A.D. are thus the simplest explanation for the differences between the contemporary and the Bronze-Age mitochondrial DNAs of Tuscany. Accordingly, genealogical continuity between ancient and modern populations of the same area does not seem a safe general assumption, but rather a hypothesis that, when possible, should be tested using ancient DNA analysis.

Link

March 07, 2008

mtDNA of Altaian Kazakhs from Russia

From the paper:
In this study, we also find that all Turkic and Mongolic groups possess a common set of maternal haplogroups (C, D, G2a, H), and a minimal number of haplotypes from these lineages at appreciable frequencies. However, the overall patterns of haplotype sharing amongst these groups vary considerably. This finding is not necessarily incompatible with the cultural diffusion model per se, but implies that present day Turkic-Mongolic ethnic groups emerged from a common mtDNA pool that was widely distributed in Central and East Asia.
This suggests that the movements of Turkic-Mongolic people did not consist only of males but also had a female component to them. Also of interest from the paper:
Haplogroup N1a was also present in the Altaian Kazakhs. Seeing as how there were no occurrences of this lineage in other Kazakh populations or neighboring populations (Kolman et al., 1996; Comas et al., 1998; Yao et al., 2004), this finding was intriguing (Table 3). The haplotypic variation within the seven N1a samples was relatively high (Table 2), with these haplotypes belonging to both the European and Central Asian branches of this haplogroup, as recently defined by Haak et al. (2005). Thus, the source of N1a haplotypes in Altaian Kazakhs was unclear, although they seemed to have originated west of this part of Central Asia (Gokcumen et al., 2007).
Interestingly, mtDNA haplogroup N1a also pops up in Havik Brahmins from India, ancient high status Hungarians, as well as Iron Age Kazakhstan, and Neolithic Central Europeans.

American Journal of Physical Anthropology (early view)

Genetic variation in the enigmatic Altaian Kazakhs of South-Central Russia: Insights into Turkic population history

Omer Gokcumen et al.

The Altaian Kazakhs, a Turkic speaking group, now reside in the southern part of the Altai Republic in south-central Russia. According to historical accounts, they are one of several ethnic and geographical subdivisions of the Kazakh nomadic group that migrated from China and Western Mongolia into the Altai region during the 19th Century. However, their population history of the Altaian Kazakhs and the genetic relationships with other Kazakh groups and neighboring Turkic-speaking populations is not well understood. To begin elucidating their genetic history, we analyzed the mtDNAs from 237 Altaian Kazakhs through a combination of SNP analysis and HVS1 sequencing. This analysis revealed that their mtDNA gene pool was comprised of roughly equal proportions of East (A-G, M7, M13, Y and Z) and West (H, HV, pre-HV, R, IK, JT, X, U) Eurasian haplogroups, with the haplotypic diversity within haplogroups C, D, H, and U being particularly high. This pattern of diversity likely reflects the complex interactions of the Kazakhs with other Turkic groups, Mongolians, and indigenous Altaians. Overall, these data have important implications for Kazakh population history, the genetic prehistory of the Altai-Sayan region, and the phylogeography of major mitochondrial lineages in Eurasia.

Link

July 18, 2007

Ancient Hungarian mtDNA

See also mtDNA of Hungarians.

Am J Phys Anthropol. 2007 Jul 13; [Epub ahead of print]

Comparison of maternal lineage and biogeographic analyses of ancient and modern Hungarian populations.

Tömöry G et al. 

The Hungarian language belongs to the Finno-Ugric branch of the Uralic family, but Hungarian speakers have been living in Central Europe for more than 1000 years, surrounded by speakers of unrelated Indo-European languages. In order to study the continuity in maternal lineage between ancient and modern Hungarian populations, polymorphisms in the HVSI and protein coding regions of mitochondrial DNA sequences of 27 ancient samples (10th-11th centuries), 101 modern Hungarian, and 76 modern Hungarian-speaking Sekler samples from Transylvania were analyzed. The data were compared with sequences derived from 57 European and Asian populations, including Finno-Ugric populations, and statistical analyses were performed to investigate their genetic relationships. Only 2 of 27 ancient Hungarian samples are unambiguously Asian: the rest belong to one of the western Eurasian haplogroups, but some Asian affinities, and the genetic effect of populations who came into contact with ancient Hungarians during their migrations are seen. Strong differences appear when the ancient Hungarian samples are analyzed according to apparent social status, as judged by grave goods. Commoners show a predominance of mtDNA haplotypes and haplogroups (H, R, T), common in west Eurasia, while high-status individuals, presumably conquering Hungarians, show a more heterogeneous haplogroup distribution, with haplogroups (N1a, X) which are present at very low frequencies in modern worldwide populations and are absent in recent Hungarian and Sekler populations. Modern Hungarian-speaking populations seem to be specifically European. Our findings demonstrate that significant genetic differences exist between the ancient and recent Hungarian-speaking populations, and no genetic continuity is seen.

Link

March 03, 2007

AAPA 2007 abstracts

The 2007 meeting of the American Association of Physical Anthropologists will be held in about a month. As in previous years, here are some interesting abstracts to be presented at the meeting (pdf).

(up to page 94)

Homo floresiensis Cranial and Mandibular Morphology
J.Y. Anderson, University of New Mexico
These results suggest the Flores material does not represent a population derived from Australomelanesians, and do not represent a non-pathological dwarfed population of Homo sapiens. These results do not completely rule out a representation of a microcephalic dwarfed population, at the same time it is suggested possible affinities to earlier hominin groups is equally parsimonious.

Do Qafzeh and Skhūl represent the ancestors of Upper Paleolithic modern humans? A dental perspective.
S.E. Bailey et al.
If these fossils represent the source of early Upper Paleolithic people, there is no need to invoke admixture with Neandertals to explain archaic dental features observed in some early Upper Paleolithic humans.

Ancient Cemetery Social Patterning Project: Ancient DNA in Tirup Cemetery.
L.E. Baker et al.

Reconstructing the settlement history of the central Andes from mitochondrial DNA analyses.
K. Batai et al.
We found that among central Andean ancient and modern population samples, haplogroup B frequencies increased through time, while haplogroup A frequencies declined. At this point, we do not yet have sufficient data to determine whether these patterns indicate different population histories between ancient coastal and modern highland populations, or a larger temporal trend in entire central Andes region

Analysis of Genetic Diversity in Ethnic Populations of Afghanistan
P. Bermudez et al.
The Middle East has the distinction of being a major crossroads of human migration. The genetic diversity of Afghanistan, however, has long remained a missing piece to this rich and complex puzzle. To explore both the diversity within Afghanistan and to understand the relative genetic contributions from various groups throughout the Eurasian continent, buccal swabs were collected from 252 unrelated Afghani men for mitochondrial DNA analysis. Each of these men hailed from
one of four major ethnic groups inhabiting the region: the Pashtun, Hazara, Tajik or
Nooristani. The Indo-Iranian speaking Pashtun represent the largest ethnic group in Afghanistan; the Tajiks have a complex genetic history that likely involves admixture between Turkic groups and smaller distinct ethnic groups within Afghanistan; the Hazara, on the other hand, are thought to represent remnants of Ghengis Khan’s army left behind as it expanded through Asia; and the Nooristani have biological links to populations in northern Pakistan and the
claim of descent from Alexander the Great’s army. All samples were analyzed for HVS1
and SNP variation. In all of these populations, Western Eurasian haplogroups (H, HV, R, J, I, U, X) were most common, with the highest frequency occurring in the Nooristanis, while the remaining East Eurasian haplogroups including D, G, and various other M types. The results of this study will be instrumental in expanding our knowledge of Afghani genetic history, in addition to broadening our understanding of population migrations throughout West and Central Asia.

Dental variation in Holocene Khoesan populations.
W. Black et al.

Are the Koh an indigenous population of the Hindu Kush? II: a dental morphology investigation.

S. Blaylock and B.E. Hemphill

Little is known about the population history of the ethnic groups in Chitral District, Pakistan, an area long been regarded as the “crossroads of Asia.” Some scholars emphasize that the Koh lifeway is the consequence of long-standing indigenous isolation. Others stress the equestrian
tradition among Koh villagers indicate they are descendants of Central Asians who emigrated across the Hindu Kush Mountains during the second millennium BC. To still others, an array of Persian linguistic inclusions indicates the Koh are more recent emigrants from the Iranian Plateau. This investigation tests these hypotheses for Koh origins through assessment of dental
morphology variations of the permanent dentition scored as 17 tooth-trait combination in accordance with the Arizona State University Dental Morphology System in a sample of 134 Kho school children from Chitral City. These data were contrasted with 17 additional samples. Comparisons are in two stages and include cluster analysis, multidimensional scaling and principal coordinates analysis. First, sex-pooled and sex-specific data compared Koh to six contemporary ethnic groups from India. Results indicate the Koh share equidistant affinities to Indo-European speaking west-Central Indian and Dravidianspeaking South Indian ethnic groups.
Second, sex-pooled data compared the Koh to 13 prehistoric samples from Neolithic to Early Iron Age sites located in the Indus Valley, Central Asia and the Iranian Plateau. Results indicate that the Koh share little affinity to prehistoric Indus Valley groups. Rather, the Koh share nearly equal affinities to prehistoric inhabitants of the Iranian Plateau and Central Asia.


A Howells grasp on prehistoric and recent Japan: A precursor to the Kennewick connection.
C. L. Brace, N. Seguchi.
Using many more samples, our results are compatible with what Howells showed for his Japanese comparisons, and,using the neighbor-joining technique, we can go on to show that Kennewick ties with the Ainu who are the descendants of the Jōmon.The Jōmon then are the probable ancestors of
the first inhabitants of the western hemisphere.

Admixture in Mexico City: implications for admixture mapping.
E. Cameron et al.
"The average proportions of Native American, European and West African admixture were estimated as 65%, 30% and 5% respectively."

"In a logistic model with higher educational status as dependent variable, the odds ratio for higher educational status associated with an increase from 0 to 1 in European admixture proportions was 9.4 (95% credible interval 3.8 – 22.6). This association of socioeconomic status with individual admixture proportion shows that genetic stratification in this population is
paralleled, and possibly maintained, by socioeconomic stratification."

Intracontinental Distribution of Haplotype Variation: Implications for Human Demographic History.
M.C. Campbell et al.
"These results suggest that diverse African populations were more subdivided with lower levels of gene flow during human history."

Social stratification in a Christian cemetery? An assessment of stress indicators and social status at Anglo-Saxon Raunds.
E.F. Craig, J.L. Buckberry
"The occurrence of statistically more individuals with both cribra orbitalia and tibial periostitis in plain graves rather than graves with stone arrangements, and LEH in plain graves rather than graves with a cover or marker, suggests that individuals buried in more elaborate graves enjoyed better levels of health and may been of higher social status than those buried in plain graves."

Variability of the Stature of the Central European Population from the Neolithic Age to Present
M. Dobisíková, S. Katina, P. Velemínský
The aim of our contribution is to characterize the changes of the stature in adult populations that have lived in Central Europe from the Neolithic period up to the present. Our sample consisted of 802 male and 704 female skeletons. The evaluation was conducted taking into account the demographic structure of the groups studied. We confronted the findings with the living
conditions of the populations known to have a significant impact on human stature, in
addition to genetic factors. We thus considered the socioeconomic status of the populations that might have influenced the quality of nutrition. We focused our attention on the socioeconomic aspect of populations of the early Middle Ages and the recent population. We compared socially higher placed part of the society with socially poorer classes (agricultural groups) (177 male, 178 female) in the early-medieval population of Great Moravia. No statistically significant
differences were found among individual social groups. To calculate the stature of last populations we used the regression equations developed by Breitiger (1937) and Bach (1965). The
calculation was based only on the length of the femur that is directly involved in body length. The impact of the secular trend was evaluated in the recent population. We compared two autopsy skeletal samples from the beginning and ends of the 20th century (107 male, 53 female). Statistically significant differences between them was found. Finally, we proposed regression equations for calculating the stature of the contemporary Czech population usable in forensic practice.

A phylogeographic analysis of haplogroup D5 and its implications for the peopling of East Asia.
M.C. Dulik
While genetic studies have focused on the Altai region of South Siberia as a possible place of origin for Native Americans, it is also possible that it played a similarly significant role in the peopling of East Asia. A Siberian connection to other East Asian populations has already been proposed based on archaeological, linguistic and classical genetic marker evidence. In this study, we examined a rare and ancient haplogroup, D5c, in an effort to elucidate early population movements in East Asia. Previous studies suggested that D5 first emerged in China and
spread northwards from there. However,given the number of D5c individuals (12) and the range of variation in D5 from the Altai region, it is conceivable that this haplogroup instead originated in South Siberia and spread from there during the initial movements of Paleolithic peoples. To est this hypothesis, we obtained complete mtDNA sequences for individuals represented by aplogroups D4 and D5 and acquired additional sequences available through GenBank and published literature. We then analyzed the entire dataset with the reduced median network approach and
phylogeographic modeling. Our results suggest that Southern Siberia did play a
critical role in the spread of the D5 haplogroup. This focus on relatively unique
mtDNA lineages specific to certain populations allowed us to better understand
the processes of ancient settlement and subsequent population movements that helped shape the current genetic landscape of East Asia.

More than meets the eye: LB1, the transforming hominin.
R.B. Eckhard et al.

LB1 is not a microcephalic.
D. Falk1 et al.

Is there biological meaning to “Hispanic” in New Mexico?
H.J.H. Edgar, C.M. Willermet

Establishing the nature of the differences between skull samples from two populations.
S.P. Evans et al.
A sample of 1188 skulls from the Romano-British site at Poundbury shows differences from the 18th century sample of 822 skulls from Spitalfields. Both sites are in the south of England, but 1400 years apart in time. The differences between the sites could be due to immigrations over time and/or to adaptation to the environment. The aim of the study was to establish the nature of the differences, in particular the relative importance of genetic and acquired traits.
Frequencies of 22 selected non-metric traits in juvenile, female and male skulls were analysed. Initial logistic regression analyses established that there was a substantial difference between the two sites and between juveniles and adults, with some sexual dimorphism. The modified mean
measure of divergence, used to calculate overall distances between the groups, showed the juvenile groups to be closer to each other than to adults from their respective sites. Across sites, males were most distant from each other. The largest distance was between Spitalfields juveniles and males. Principal coordinate analysis, followed by a jackknife stability analysis, revealed a pattern indicating that this came about through growth and adaptation. Omitting traits in turn, procrustes methods were used to identify the most influential, all of which
were acquired through ageing or lifestyle. Without these traits there was no significant
difference between the two juvenile groups and no sexual dimorphism. These results show the importance of the behavioural environment in determining morphology, and the resilience of populations to genetic change.

Peopling of the Pacific: resolving the controversy.
J.S. Friedlaender et al.
"Our survey of mitochondrial DNA, Ychromosome, and over 600 short tandem repeat polymorphisms and 200 insertiondeletions from over 40 Pacific populations indicates Polynesians have their genetic
origins to both Melanesian and Taiwanese (Southeast Asian) populations in significant degrees. In Island Melanesia, there is a small but clear ancient genetic footprint in certain Oceanic-speaking populations (i.e., linguistically related to Polynesian). The survey results underscore the extraordinary diversity of Island Melanesian populations from one language group to another, and from island to island. This is the result of the small sizes of the populations and the very long extent of modern human settlement there (over 30,000 years)."

Multivariate studies of cranial form: the impact of Howells' research on defining Homo sapiens.
J.B. Gaines et al.

Demographic simulations of the admixture between foragers and farmers in central European Neolithic.
P. Galeta, J. Bruzek.

William White Howells: A physical anthropologist in the making.
E. Giles

The relationship of Nubians with their neighbors, the Egyptians.
By, K. Godde.

The Phylogeography of Haplogroup N1a
Gokcumen O et al.
Recent studies have revealed a complex geographic distribution of haplogroup N1a. This rare and distinctive lineage is widely distributed across Eurasia and Africa, but always found at very low frequencies. However, despite its rarity, the genetic diversity within N1a has remained relatively high (h=0.9605). The reduced median network of N1a haplotypes not only reflects
this level of diversity, but also exhibits several relatively well-defined branches. The
distribution of N1a is intriguing because of revealing previously unrecognized connections between populations. What makes N1a even more interesting is the prevalence of this lineage in ancient European populations. Haak et al. (2005) found that 25% of their European Neolithic
samples belonged to N1a and dated to ~5000 BCE, whereas the frequency of this lineage in contemporary Europeans is only ~0.2%. In addition, an Iron Age skeleton from Kazakhstan had an N1a haplotype, suggesting the existence of this lineage in the Altai Republic in ~500BCE (Ricaut et al. 2004). Indeed, we found several haplogroup N1a mtDNAs in indigenous Altaians and Altaian Kazakhs. To further elucidate the phylogeography of this lineage in Central Asia, we sequenced the whole mtDNA genomes of our N1a haplotypes, and analyzed the resulting data with several quantitative methods and simulation programs to estimate their expansion times and spatial
distribution in Eurasia. Our findings suggest that there are two well-defined sublineages
within N1a, and that the dispersal of this haplogroup could be associated with the Neolithic expansion and with prehistoric interactions between Central Asian and European populations.



Understanding human races: the retreat of neutralism.
Henry Harpending
Discussion and debate about human races has been dominated for decades by neutral theory and statistics. Since this literature never posed a real question, it has never produced an answer. Lewontin's 1972 paper with its claim that a value of 1/8 of a statistic like Fst is “small” and that this means that human race differences are insignificant is a staple of our textbooks. Recently geneticists have had a closer look and pointed out that Fst of 1/8 describes differences among sets of half sibs and few claim that half sibs are insignificantly related. Anthony Edwards has shown that the significance of differences is in the correlation structure of a large number of traits, again denying the Lewontin assertion that human differences are small. Alan Templeton in 1998 claimed that human races were less differentiated that races of some other large mammals, but he compared human nuclear DNA statistics with statistics from mtDNA in the other species. An appropriate comparison shows that human are more, not less, differentiated than other large mammal species. Since neutral differences are a passive
record of demographic history they are not very significant for issues of functional biology. Newly available data sources allow us to study the natural selection of race differences instead of their drift. It appears that there is a lot of ongoing evolution in our species and the loci under strong selection on different continents only partially overlap. Human race differences may be increasing rapidly.

Acceleration of adaptive evolution in modern humans.
J. Hawks and G. Cochran
Humans vastly increased in numbers during the past 40,000 years. Recent surveys of human genomic variation have suggested a large surplus of recent positive selection, indicated by excess linkage disequilibrium and skewed SNP frequency spectra. We applied estimates of prehistoric and historic population sizes to estimate the importance of population growth in explaining the number of recent adaptive mutations. Our estimates are consistent with genomic evidence in suggesting that the rate of generation of positively selected genes has increased as much as a hundredfold during the past 40,000 years.

Do skeletal features reflect this genomic evidence of selection? Under positive
selection, rapid appearance of new variants during the terminal Pleistocene and early
Holocene would cause maximal phenotypic change during the last 2000-4000 years. We compared original and published series of Holocene cranial data from Europe, Jordan, Nubia, South Africa, and China, in addition to Late Pleistocene samples from Europe and West Asia, to test the hypothesis that the genomic acceleration in positive selection correlates with phenotypic evolution during this time period. A constellation of features in the face and cranial vault, notably including endocranial volume, changed globally during this time period and documents common patterns of selection in different regions. Holocene changes were similar in pattern and chronologically faster than those at the archaic-modern transition, which themselves were rapid compared to earlier hominid evolution. In genomic and craniometric terms, the origin of modern humans was a minor event compared to more recent evolutionary changes.

Patterns of admixture in Mexican Americans assessed from 101,150 SNPs.
M.G. Hayes et al.
"No significant differences were observed between the 10 subsets, allowing us to average the admixture estimates across the subsets: 68% European, 27% Asian (as a proxy for Native American), and 6% African."

Gender, wealth, and status in Bronze Age Central Asia: a dental pathology investigation.
B.E. Hemphill.

Sahara passage: the post-glacial recolonisation of North Africa by mitochondrial L* haplotypes.
AD Holden. P Forster.

Secular trends of the European male facial skull from the Migration Period to the present.
E. Jonke et al.
We examined secular trends in the facial skull over three Central European samples spanning more than 13 centuries. Data are 43 conventional cephalometric landmark points for samples dating from 680–830 CE, from the mid-19th Century, and from living Austrian young adult males. Methods of geometric morphometrics demonstrate shape differences across the samples, and also
differences in allometry. There is a stronginteraction between these, so that group mean differences are different for small and large individuals (equivalently, allometry is
different from period to period). The oldest sample, from the Migration Period, exhibits
allometric features that may possibly be Turkic
. There are implications for the
craniofacial biologist interested in growth trends or growth predictions in ethnically
mixed populations. There are also implications for the discussion concerning the morphology of the Avars (an ethnic group of probably Central Asian origin who conquered large parts of Central Europe during the Migration Period and who interbred with other incoming groups after their conquest by Charlemagne), and also the relation of these findings to current thinking on gnathic reduction trends.

Roman Gladiators - The Osseous Evidence.
F. Kanz, K. Grossschmidt

Paternal heritage for the Indonesian peoples.
T. M. Karafet et al.

Feeding the children: Isotopic evidence for weaning practices in the ancient Greek colony of Apollonia (5th-2nd centuries BC).
C. Kwok, A. Keenleyside.

Misconceptions about the postcranial skeleton of Homo floresiensis.
S.G. Larson et al.

A comparison of mitochondrial DNA and Y chromosome DNA variation on Manus Island.
K.E. Latham et al.