Mating patterns amongst Siberian reindeer herders: inferences from mtDNA and Y-chromosomal analyses

The Evenks and Evens, who speak closely related languages belonging to the Northern Tungusic branch of the Tungusic family, are nomadic reindeer herders and hunters. They are spread over an immense territory in northeastern Siberia, and consequently different subgroups are in contact with diverse peoples speaking Samoyedic, Turkic, Mongolic, Chukotka-Kamchatkan, and Yukaghir languages. Nevertheless, the languages and culture of the Evenks and Evens are similar enough for them to have been classified as a single ethnic group in the past. This linguistic and cultural similarity indicates that they may have spread over their current area of habitation relatively recently, and thus may be closely related genetically. On the other hand, the great distances that separate individual groups of Evens and Evenks from each other might have led to preferential mating with geographic neighbors rather than with linguistically related peoples. In this study, we assess the correlation between linguistic and genetic relationship in three different subgroups of Evenks and Evens, respectively, via mtDNA and Y-chromosomal analyses. The results show that there is some evidence of a common origin based on shared mtDNA lineages and relatively similar Y-haplogroup frequencies amongst most of the Evenk and Even subgroups. However, there is little sharing of Y-chromosomal STR haplotypes, indicating that males within Evenk and Even subgroups have remained relatively isolated. There is further evidence of some female admixture in different Even subgroups with their respective geographic neighbors. However, the Tungusic groups, and especially the Evenks, show signs of genetic drift, making inferences about their prehistory difficult.     

Extensive ethnolinguistic diversity at the crossroads of North China and South Siberia reflects multiple sources of genetic diversity

North China and South Siberia, populated by Altaic- and Sino-Tibetan-speaking populations, possess extensive ethnolinguistic diversity and serve as the crossroads for the initial peopling of America and western–eastern transcontinental communication. However, the population genetic structure and admixture history of northern East Asians remain poorly understood due to a lack of genome-wide data, especially for Mongolic-speaking people in China. We genotyped genome-wide single nucleotide polymorphisms for 510 individuals from 38 Mongolic, Tungusic, and Sinitic-speaking populations. We first explored the shared alleles and haplotypes within the studied groups. We then merged with 3508 published modern and ancient Eurasian individuals to reconstruct the deep evolutionary and natural selection history of northern East Asians. We identified genetic substructures within Altaic-speaking populations: Western Turkic people harbored more western Eurasian-related ancestry; Northern Mongolic people in Siberia and eastern Tungusic people in Amur River Basin (ARB) possessed a majority of Neolithic ARB related ancestry; Southern Mongolic people in China possessed apparent genetic influence from Neolithic Yellow River Basin (YRB) farmers. Additionally, we found the differentiated admixture history between western and eastern Mongolians and geographically close Northeast Hans: the former received a genetic impact from western Eurasians, and the latter retained the primary Neolithic YRB and ARB ancestry. Moreover, we demonstrated that Kalmyk people from the northern Caucasus Mountains possessed a strong genetic affinity with Neolithic Mongolian Plateau (MP) people, supporting the hypothesis of their eastern Eurasian origin and long-distance migration history. We also illuminated that historical pastoral empires in the MP contributed considerably to the gene pool of northern Mongolic people but rarely to the southern ones. We finally found natural selection signatures in Mongolians associated with alcohol metabolism. Our results demonstrated that the Neolithic ancestral sources from the MP or ARB played an important role in spreading Altaic populations and languages. The observed multisources of genetic diversity contributed significantly to the extensive ethnolinguistic diversity in northern East Asia.     

Y-chromosome variation in Altaian Kazakhs reveals a common paternal gene pool for Kazakhs and the influence of Mongolian expansions

Kazakh populations have traditionally lived as nomadic pastoralists that seasonally migrate across the steppe and surrounding mountain ranges in Kazakhstan and southern Siberia. To clarify their population history from a paternal perspective, we analyzed the non-recombining portion of the Y-chromosome from Kazakh populations living in southern Altai Republic, Russia, using a high-resolution analysis of 60 biallelic markers and 17 STRs. We noted distinct differences in the patterns of genetic variation between maternal and paternal genetic systems in the Altaian Kazakhs. While they possess a variety of East and West Eurasian mtDNA haplogroups, only three East Eurasian paternal haplogroups appear at significant frequencies (C3*, C3c and O3a3c*). In addition, the Y-STR data revealed low genetic diversity within these lineages. Analysis of the combined biallelic and STR data also demonstrated genetic differences among Kazakh populations from across Central Asia. The observed differences between Altaian Kazakhs and indigenous Kazakhs were not the result of admixture between Altaian Kazakhs and indigenous Altaians. Overall, the shared paternal ancestry of Kazakhs differentiates them from other Central Asian populations. In addition, all of them showed evidence of genetic influence by the 13(th) century CE Mongol Empire. Ultimately, the social and cultural traditions of the Kazakhs shaped their current pattern of genetic variation.     

Denisova admixture and the first modern human dispersals into Southeast Asia and Oceania

It has recently been shown that ancestors of New Guineans and Bougainville Islanders have inherited a proportion of their ancestry from Denisovans, an archaic hominin group from Siberia. However, only a sparse sampling of populations from Southeast Asia and Oceania were analyzed. Here, we quantify Denisova admixture in 33 additional populations from Asia and Oceania. Aboriginal Australians, Near Oceanians, Polynesians, Fijians, east Indonesians, and Mamanwa (a "Negrito" group from the Philippines) have all inherited genetic material from Denisovans, but mainland East Asians, western Indonesians, Jehai (a Negrito group from Malaysia), and Onge (a Negrito group from the Andaman Islands) have not. These results indicate that Denisova gene flow occurred into the common ancestors of New Guineans, Australians, and Mamanwa but not into the ancestors of the Jehai and Onge and suggest that relatives of present-day East Asians were not in Southeast Asia when the Denisova gene flow occurred. Our finding that descendants of the earliest inhabitants of Southeast Asia do not all harbor Denisova admixture is inconsistent with a history in which the Denisova interbreeding occurred in mainland Asia and then spread over Southeast Asia, leading to all its earliest modern human inhabitants. Instead, the data can be most parsimoniously explained if the Denisova gene flow occurred in Southeast Asia itself. Thus, archaic Denisovans must have lived over an extraordinarily broad geographic and ecological range, from Siberia to tropical Asia.     

Genetic diversity and relationships of populations of northern Eurasia by polymorphic Alu insertions

Autosomal gene pools of 27 populations representing 12 ethnic groups of Siberia, Central Asia, and the Far East have been characterized for the first time using a set of eight polymorphic Alu insertions. The results of our analysis indicate a significant level of genetic diversity in populations of northern Eurasian and the considerable differentiation of their gene pool. It was shown that the frequency of the Alu (?) allele at the CD4 locus was inversely related to the magnitude of the Mongoloid component of the gene pool: the lowest and highest frequencies of the CD4 Alu deletion were recorded in Eskimos (0.012) and in Russians and Ukrainians (0.35), respectively. A gene flow analysis showed that Caucasoid populations (Russians, Tajiks, and Uzbeks), as well as Turkic ethnic groups of southern Siberia (Altaians and Tuvans), Khanty, and Mansi populations, in contrast to ethnic groups of eastern Siberia and the Far East, have been recipients of a considerable gene flow. A correlation analysis showed that genetic distances determined using polymorphic Alu insertions were correlated with the anthropological characteristics of the populations studied.     

Investigating the Prehistory of Tungusic Peoples of Siberia and the Amur-Ussuri Region?with Complete mtDNA Genome Sequences and Y-chromosomal Markers

Evenks and Evens, Tungusic-speaking reindeer herders and hunter-gatherers, are spread over a wide area of northern Asia, whereas their linguistic relatives the Udegey, sedentary fishermen and hunter-gatherers, are settled to the south of the lower Amur River. The prehistory and relationships of these Tungusic peoples are as yet poorly investigated, especially with respect to their interactions with neighbouring populations. In this study, we analyse over 500 complete mtDNA genome sequences from nine different Evenk and even subgroups as well as their geographic neighbours from Siberia and their linguistic relatives the Udegey from the Amur-Ussuri region in order to investigate the prehistory of the Tungusic populations. These data are supplemented with analyses of Y-chromosomal haplogroups and STR haplotypes in the Evenks, Evens, and neighbouring Siberian populations. We demonstrate that whereas the North Tungusic Evenks and Evens show evidence of shared ancestry both in the maternal and in the paternal line, this signal has been attenuated by genetic drift and differential gene flow with neighbouring populations, with isolation by distance further shaping the maternal genepool of the Evens. The Udegey, in contrast, appear quite divergent from their linguistic relatives in the maternal line, with a mtDNA haplogroup composition characteristic of populations of the Amur-Ussuri region. Nevertheless, they show affinities with the Evenks, indicating that they might be the result of admixture between local Amur-Ussuri populations and Tungusic populations from the north.     

Brief communication: Y-chromosome haplogroup analysis indicates that Chinese Tuvans share distinctive affinity with Siberian Tuvans

Tuvans are mainly distributed in Siberia (the Republic of Tuva), Mongolia, and China. The genetic origin of Chinese Tuvans remains controversial. The Tuvans in China were classified as Mongolians in the early 1950s by the National Ethnic Affairs Commission of China, but they defined themselves as a separate group. To resolve this dispute and determine their genetic relationships with the peoples in Central Asia, we randomly selected 150 male subjects from the Tuvans in the Altai region of Xinjiang Uygur Autonomous Region in China. Fourteen Y chromosomal markers were genotyped using the RFLP method or direct sequencing. These haplogroup data were combined with public data for 15 populations in South Siberia and Central Asia. Tuvans in both China and the Republic of Tuva had the highest frequencies of haplogroups K-M9 and Q-M242. Principal component analysis demonstrated that the Tuvans in China were of a distinct cluster, separated from their neighbors, the Mongolians and Kazakhs, which finding was consistent with the Analysis of Molecular Variances. Further population tree analysis revealed that Tuvans were on a far-separated cluster from their neighbors. Based on these results, we propose that the Tuvans (in both China and the Republic of Tuva) constitute a group distinct from Mongolians and from other Central Asia populations. However, the genetic results might be the consequence of some evolutionary forces like genetic drift and founder effect, and do not necessarily reflect their ultimate origin.     

Diversity of Mitochondrial DNA Haplogroups in Ethnic Populations of the Volga–Ural Region

The mtDNA polymorphism was analyzed in eight ethnic groups (N = 979) of the Volga–Ural region. Most mtDNA variants belonged to haplogroups H, U, T, J, W, I, R, and N1 characteristic of West Eurasian populations. The most frequent were haplogroups H (12–42%) and U (18–44%). East Eurasian mtDNA types (A, B, Y, F, M, N9) were also observed. Genetic diversity was higher in Turkic than in Finno-Ugric populations. The frequency of mtDNA types characteristic of Siberian and Central Asian populations substantially increased in the ethnic groups living closer to the Urals, a boundary between Europe and Asia. Geographic distances, rather than linguistic barriers, were assumed to play the major role in distribution of mtDNA types in the Volga–Ural region. Thus, as concerns the maternal lineage, the Finno-Ugric populations of the region proved to be more similar to their Turkic neighbors rather than to linguistically related Balto-Finnish ethnic groups.     

Importance of demographic history for phylogeographic inference on the arctic–alpine plant Phyllodoce caerulea in East Asia

Arctic–alpine plants have enormous ranges in the Northern Hemisphere. Phylogeographic studies have provided insights into their glacial survival as well as their postglacial colonization history. However, our understanding of the population dynamics of disjunct alpine populations in temperate regions remains limited. During Pleistocene cold periods, alpine populations of arctic–alpine species in East Asia were either connected to an ice-free Beringia refugium or they persisted with prolonged isolation after their establishment. To estimate which of these scenarios is more likely, we elucidated the genetic structure of Phyllodoce caerulea (Ericaceae) in Beringia and northern Japan, East Asia. Sequence variation in multiple nuclear loci revealed that P. caerulea can be distinguished into northern and southern groups. A demographic analysis demonstrated that the north–south divergence did not predate the last glacial period and detected introgression from Phyllodoce aleutica, relative widely distributed in East Asia, exclusively into the southern group. Therefore, although there has been genetic divergence between northern Japan and Beringia in P. caerulea, the divergence is unlikely to have resulted from their prolonged geographic separation throughout several cycles of glacial and interglacial periods. Instead, our study suggests that the introgression contributed to the genetic divergence of P. caerulea and that the range of P. caerulea was plausibly connected between northern Japan and Beringia during the last glacial period. Overall, our study not only provides a biogeographic insight into alpine populations of arctic–alpine plants in East Asia but also emphasizes the importance of careful interpretation of genetic structure for inferring phylogeographic history.     

Mitochondrial DNA evidence for admixed origins of central Siberian populations

The Yakuts of northeastern Siberia are a Turkic-speaking population of horse- and cattle-breeders surrounded by Tungusic-speaking reindeer-herders and hunter-gatherers. Archaeological and ethnohistorical data suggest that Yakuts stem from a common ancestral population with the Buryats living near Lake Baikal. To address this hypothesis, we obtained sequences of the first hypervariable segment (HV1) of the mitochondrial DNA control region from Yakuts and Buryats and compared these with sequences from other Eurasian populations. The mtDNA results show that the Buryats have close affinities with both Central Asian Turkic groups and Mongols, while the Yakuts have close affinities with northeastern Siberian, Tungusic-speaking Evenks and south Siberian, Turkic-speaking Tuvans. This different ancestry of the Yakuts and the Tuvans (compared with other Turkic-speaking groups) most likely reflects extensive admixture that occurred between Turkic-speaking steppe groups and Evenks as the former migrated into Siberia. Moreover, the Yakuts are unique among Siberian populations in having a high number of haplotypes shared exclusively with Europeans, suggesting, contrary to the historical record, that occasionally Yakut men took Russian women as wives.     

Human evolution in Siberia: from frozen bodies to ancient DNA

Background  

The Yakuts contrast strikingly with other populations from Siberia due to their cattle- and horse-breeding economy as well as their Turkic language. On the basis of ethnological and linguistic criteria as well as population genetic studies, it has been assumed that they originated from South Siberian populations. However, many questions regarding the origins of this intriguing population still need to be clarified (e.g. the precise origin of paternal lineages and the admixture rate with indigenous populations). This study attempts to better understand the origins of the Yakuts by performing genetic analyses on 58 mummified frozen bodies dated from the 15^th to the 19^th century, excavated from Yakutia (Eastern Siberia).     

Testing hypotheses of language replacement in the Caucasus: evidence from the Y-chromosome

A previous analysis of mtDNA variation in the Caucasus found that Indo-European-speaking Armenians and Turkic-speaking Azerbaijanians were more closely related genetically to other Caucasus populations (who speak Caucasian languages) than to other Indo-European or Turkic groups, respectively. Armenian and Azerbaijanian therefore represent language replacements, possibly via elite dominance involving primarily male migrants, in which case genetic relationships of Armenians and Azerbaijanians based on the Y-chromosome should more closely reflect their linguistic relationships. We therefore analyzed 11 bi-allelic Y-chromosome markers in 389 males from eight populations, representing all major linguistic groups in the Caucasus. As with the mtDNA study, based on the Y-chromosome Armenians and Azerbaijanians are more closely-related genetically to their geographic neighbors in the Caucasus than to their linguistic neighbors elsewhere. However, whereas the mtDNA results show that Caucasian groups are more closely related genetically to European than to Near Eastern groups, by contrast the Y-chromosome shows a closer genetic relationship with the Near East than with Europe.     

Comparative population genetics of mimetic Heliconius butterflies in an endangered habitat; Brazil's Atlantic Forest

Background

The islands of North Maluku, Indonesia occupy a central position in the major prehistoric dispersal streams that shaped the peoples of Island Southeast Asia and the Pacific. Within this region a linguistic contact zone exists where speakers of Papuan and Austronesian languages reside in close proximity. Here we use population genetic data to assess the extent to which North Maluku populations experienced admixture of Asian genetic material, and whether linguistic boundaries reflect genetic differentiation today.

Results

Autosomal and X-linked markers reveal overall Asian admixture of 67% in North Maluku, demonstrating a substantial contribution of genetic material into the region from Asia. We observe no evidence of population structure associated with ethnicity or language affiliation.

Conclusions

Our data support a model of widespread Asian admixture in North Maluku, likely mediated by the expansion of Austronesian-speaking peoples into the region during the mid Holocene. In North Maluku there is no genetic differentiation in terms of Austronesian- versus Papuan-speakers, suggesting extensive gene flow across linguistic boundaries. In a regional context, our results illuminate a major genetic divide at the Molucca Sea, between the islands of Sulawesi and North Maluku. West of this divide, populations exhibit predominantly Asian ancestry, with very little contribution of Papuan genetic material. East of the Molucca Sea, populations show diminished rates of Asian admixture and substantial persistence of Papuan genetic diversity.     

GM haplotype diversity of 82 populations over the world suggests a centrifugal model of human migrations

This study investigates the GM genetic relationships of 82 human populations, among which 10 represent original data, within and among the main broad geographic areas of the world. Different approaches are used: multidimensional scaling analysis and test for isolation by distance, to assess the correlation between genetic variation and spatial distributions; analysis of variance, to investigate the genetic structure at different hierarchical levels of population subdivision; genetic similarity map (geographic map distorted by available genetic information), to identify regions of high and low genetic variation; and minimal spanning network, to point out possible migration routes across continental areas. The results show that the GM polymorphism is characterized by one of the highest amounts of genetic variation observed so far among populations of different continents (Fct=0.3915, P < 0.0001). GM diversity can be explained by a model of isolation by distance (IBD) at most continental levels, with a particularly significant fit to IBD for the Middle East and Europe. Five peripheral regions of the world (Europe, west and south sub-Saharan Africa, Southeast Asia, and America) exhibit a low level of genetic diversity both within and among populations. By contrast, East and North African, Southwest Asian, and Northeast Asian populations are highly diverse and interconnected genetically by large genetic distances. Therefore, the observed GM variation can be explained by a "centrifugal model" of modern humans peopling history, involving ancient dispersals across a large intercontinental area spanning from East Africa to Northeast Asia, followed by recent migrations in peripheral geographic regions.     

Alu insertion polymorphisms and an assessment of the genetic contribution of Central Asia to Anatolia with respect to the Balkans

In the evolutionary history of modern humans, Anatolia acted as a bridge between the Caucasus, the Near East, and Europe. Because of its geographical location, Anatolia was subject to migrations from multiple different regions throughout time. The last, well-known migration was the movement of Turkic speaking, nomadic groups from Central Asia. They invaded Anatolia and then the language of the region was gradually replaced by the Turkic language. In the present study, insertion frequencies of 10 Alu loci (A25 = 0.07, APO = 0.96, TPA25 = 0.44, ACE = 0.37, B65 = 0.57, PV92 = 0.18, FXIIIB = 0.52, D1 = 0.40, HS4.32 = 0.66, and HS4.69 = 0.30) have been determined in the Anatolian population. Together with the data compiled from other databases, the similarity of the Anatolian population to that of the Balkans and Central Asia has been visualized by multidimensional scaling method. Analysis suggested that, genetically, Anatolia is more closely related with the Balkan populations than to the Central Asian populations. Central Asian contribution to Anatolia with respect to the Balkans was quantified with an admixture analysis. Furthermore, the association between the Central Asian contribution and the language replacement episode was examined by comparative analysis of the Central Asian contribution to Anatolia, Azerbaijan (another Turkic speaking country) and their neighbors. In the present study, the Central Asian contribution to Anatolia was estimated as 13%. This was the lowest value among the populations analyzed. This observation may be explained by Anatolia having the lowest migrant/resident ratio at the time of migrations.     

Analyses of genetic structure of Tibeto-Burman populations reveals sex-biased admixture in southern Tibeto-Burmans

An unequal contribution of male and female lineages from parental populations to admixed ones is not uncommon in the American continents, as a consequence of directional gene flow from European men into African and Hispanic Americans in the past several centuries. However, little is known about sex-biased admixture in East Asia, where substantial migrations are recorded. Tibeto-Burman (TB) populations were historically derived from ancient tribes of northwestern China and subsequently moved to the south, where they admixed with the southern natives during the past 2600 years. They are currently extensively distributed in China and Southeast Asia. In this study, we analyze the variations of 965 Y chromosomes and 754 mtDNAs in >20 TB populations from China. By examining the haplotype group distributions of Y-chromosome and mtDNA markers and their principal components, we show that the genetic structure of the extant southern Tibeto-Burman (STB) populations were primarily formed by two parental groups: northern immigrants and native southerners. Furthermore, the admixture has a bias between male and female lineages, with a stronger influence of northern immigrants on the male lineages (approximately 62%) and with the southern natives contributing more extensively to the female lineages (approximately 56%) in the extant STBs. This is the first genetic evidence revealing sex-biased admixture in STB populations, which has genetic, historical, and anthropological implications.     

Complex Patterns of Genomic Admixture within Southern Africa

Within-population genetic diversity is greatest within Africa, while between-population genetic diversity is directly proportional to geographic distance. The most divergent contemporary human populations include the click-speaking forager peoples of southern Africa, broadly defined as Khoesan. Both intra- (Bantu expansion) and inter-continental migration (European-driven colonization) have resulted in complex patterns of admixture between ancient geographically isolated Khoesan and more recently diverged populations. Using gender-specific analysis and almost 1 million autosomal markers, we determine the significance of estimated ancestral contributions that have shaped five contemporary southern African populations in a cohort of 103 individuals. Limited by lack of available data for homogenous Khoesan representation, we identify the Ju/''hoan (n = 19) as a distinct early diverging human lineage with little to no significant non-Khoesan contribution. In contrast to the Ju/''hoan, we identify ancient signatures of Khoesan and Bantu unions resulting in significant Khoesan- and Bantu-derived contributions to the Southern Bantu amaXhosa (n = 15) and Khoesan !Xun (n = 14), respectively. Our data further suggests that contemporary !Xun represent distinct Khoesan prehistories. Khoesan assimilation with European settlement at the most southern tip of Africa resulted in significant ancestral Khoesan contributions to the Coloured (n = 25) and Baster (n = 30) populations. The latter populations were further impacted by 170 years of East Indian slave trade and intra-continental migrations resulting in a complex pattern of genetic variation (admixture). The populations of southern Africa provide a unique opportunity to investigate the genomic variability from some of the oldest human lineages to the implications of complex admixture patterns including ancient and recently diverged human lineages.     

Diversity of mitochondrial DNA haplotypes in ethnic populations of the Volga-Ural region of Russia

The mtDNA polymorphism was analyzed in eight ethnic groups (N = 979) of the Volga-Ural region. Most mtDNA variants belonged to haplogroups H, U, T, J, W, I, R, and N1 characteristic of West Eurasian populations. The most frequent were haplogroups H (12-42%) and U (18-44%). East Eurasian mtDNA types (A, B, Y, F, M, N9) were also observed. Genetic diversity was higher in Turkic than in Finno-Ugric populations. The frequency of mtDNA types characteristic of Siberian and Central Asian populations substantially increased in the ethnic groups living closer to the Urals, a boundary between Europe and Asia. Geographic distances, rather than linguistic barriers, were assumed to play the major role in distribution of mtDNA types in the Volga-Ural region. Thus, as concerns the maternal lineage, the Finno-Ugric populations of the region proved to be more similar to their Turkic neighbors rather than to linguistically related Balto-Finnish ethnic groups.     

Tracing the Origin of the East-West Population Admixture in the Altai Region (Central Asia)

A recent discovery of Iron Age burials (Pazyryk culture) in the Altai Mountains of Mongolia may shed light on the mode and tempo of the generation of the current genetic east-west population admixture in Central Asia. Studies on ancient mitochondrial DNA of this region suggest that the Altai Mountains played the role of a geographical barrier between West and East Eurasian lineages until the beginning of the Iron Age. After the 7th century BC, coinciding with Scythian expansion across the Eurasian steppes, a gradual influx of East Eurasian sequences in Western steppes is detected. However, the underlying events behind the genetic admixture in Altai during the Iron Age are still unresolved: 1) whether it was a result of migratory events (eastward firstly, westward secondly), or 2) whether it was a result of a local demographic expansion in a ‘contact zone’ between European and East Asian people. In the present work, we analyzed the mitochondrial DNA lineages in human remains from Bronze and Iron Age burials of Mongolian Altai. Here we present support to the hypothesis that the gene pool of Iron Age inhabitants of Mongolian Altai was similar to that of western Iron Age Altaians (Russia and Kazakhstan). Thus, this people not only shared the same culture (Pazyryk), but also shared the same genetic east-west population admixture. In turn, Pazyryks appear to have a similar gene pool that current Altaians. Our results further show that Iron Age Altaians displayed mitochondrial lineages already present around Altai region before the Iron Age. This would provide support for a demographic expansion of local people of Altai instead of westward or eastward migratory events, as the demographic event behind the high population genetic admixture and diversity in Central Asia.     

High levels of Y-chromosome differentiation among native Siberian populations and the genetic signature of a boreal hunter-gatherer way of life

We examined genetic variation on the nonrecombining portion of the Y chromosome (NRY) to investigate the paternal population structure of indigenous Siberian groups and to reconstruct the historical events leading to the peopling of Siberia. A set of 62 biallelic markers on the NRY were genotyped in 1432 males representing 18 Siberian populations, as well as nine populations from Central and East Asia and one from European Russia. A subset of these markers defines the 18 major NRY haplogroups (A-R) recently described by the Y Chromosome Consortium (YCC 2002). While only four of these 18 major NRY haplogroups accounted for -95% of Siberian Y-chromosome variation, native Siberian populations differed greatly in their haplogroup composition and exhibited the highest phiST value for any region of the world. When we divided our Siberian sample into four geographic regions versus five major linguistic groupings, analyses of molecular variance (AMOVA) indicated higher phiST and phiCT values for linguistic groups than for geographic groups. Mantel tests also supported the existence of NRY genetic patterns that were correlated with language, indicating that language affiliation might be a better predictor of the genetic affinity among Siberians than their present geographic position. The combined results, including those from a nested cladistic analysis, underscored the important role of directed dispersals, range expansions, and long-distance colonizations bound by common ethnic and linguistic affiliation in shaping the genetic landscape of Siberia. The Siberian pattern of reduced haplogroup diversity within populations combined with high levels of differentiation among populations may be a general feature characteristic of indigenous groups that have small effective population sizes and that have been isolated for long periods of time.