November 03, 2005

Y chromosomes of South Siberians

A very interesting paper about South Siberia, a contact region between Caucasoids and Mongoloids right in the middle of Asia. First, the anthropological picture, which has been established for quite some time:
Unfortunately, archaeological records alone with the lack of human skeletal remains are inconclusive about the anthropological traits, which were characteristic for the Upper Paleolithic Siberian population. East Asian features thought to have been derived from early modern East Asians exist in the tooth from the Denisova Cave in the Altai region and in human remains from the Afontova Gora II site and indicate that the East Asians had moved into southwestern Siberia by 21,000 B.P. or even earlier (Alekseev 1998). Yet, the Upper Paleolithic artifacts from the 23,000-year-old Mal’ta site near Lake Baikal in south-central Siberia (Medvedev et al. 1996) have been found in association with skeletal remains that bear similar morphology with contemporary anatomically modern humans teeth from Europe thus providing the evidence for links between Siberia and the West during the Upper Paleolithic. Thus, on assuming that during the Upper Paleolithic the population of South Siberia was closely related to other East Asian populations, then during the Neolithic, admixture with populations from Eastern Europe probably occurred. The prevalence of European features among steppe zone inhabitants of Tuva, Altai, Khakassia, and West Mongolia became the most significant since the Bronze Age or even earlier (Alexeev and Gohman 1984; Alexeev 1989). The boundary of the Eastern European influence is clearly fixed at Lake Baikal. To the east of Baikal no palaeoanthropological find bears any traces of European admixture (Alekseev 1998).
Of importance is the discovery that R1a1 chromosomes in Siberians and Eastern Europeans are differentiated, and are both quite old, predating the spread of the Kurgan culture.
Divergency estimates based on Y-chromosome microsatellite variation indicate that, despite the haplotype diversity value of Eastern European R1a1-lineages exceeds that in South Siberia, the estimated ages for this haplogroup are almost equal in both regional groups—11,270±4,070 years in South Siberia and 11,380±3,200 years in Eastern Europe. These values are very close to the divergence time between the two regional groups studied (10,310±3,140 years). These results suggest that an isolation of the regional groups occurred soon after the origin of the R1a1 haplogroup.
Finally, here are the haplogroup frequencies in the various populations tested.

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Update: The most frequent haplotype (#40) in Siberians, defined over (DYS19, DYS385a, DYS385b, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439) is: 16 11 14 14 18 25 11 11 13 14 11 10. This was not found in the extensive Russian sample, so it may represent a quite distinctive Central Asian haplotype.

Interestingly, a search in YHRD with this haplotype revealed only a single match in the Hungarian-speaking sample Lunca de Sus, Romania [Csángó]. This may serve to illustrate the paucity of relevant samples in YHRD. If we exclude DYS438 and DYS439 which are not typed in all samples in YHRD, then additional matches are found in Central Anatolian Turks, Szekely (also Hungarian-speaking) from Romania and in Ljubljana, Slovenia. If we further remove the fast-mutating DYS385 markers, then the following matches are found.

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Let's hope that more Central Asian and Siberian samples are added to YHRD soon!

Human Genetics (Early view)

Contrasting patterns of Y-chromosome variation in South Siberian populations from Baikal and Altai-Sayan regions

Miroslava Derenko et al.

Abstract In order to investigate the genetic history of autochthonous South Siberian populations and to estimate the contribution of distinct patrilineages to their gene pools, we have analyzed 17 Y-chromosomal binary markers (YAP, RPS4Y711, SRY-8299, M89, M201, M52, M170, 12f2, M9, M20, 92R7, SRY-1532, DYS199, M173, M17, Tat, and LLY22 g) in a total sample of 1,358 males from 14 ethnic groups of Siberia (Altaians-Kizhi, Teleuts, Shors, Tuvinians, Todjins, Tofalars, Sojots, Khakassians, Buryats, Evenks), Central/Eastern Asia (Mongolians and Koreans) and Eastern Europe (Kalmyks and Russians). Based on both, the distribution pattern of Y-chromosomal haplogroups and results on AMOVA analysis we observed the statistically significant genetic differentiation between the populations of Baikal and Altai–Sayan regions. We suggest that these regional differences can be best explained by different contribution of Central/Eastern Asian and Eastern European paternal lineages into gene pools of modern South Siberians. The population of the Baikal region demonstrates the prevalence of Central/Eastern Asian lineages, whereas in the populations of Altai and Sayan regions the highest paternal contribution resulted from Eastern European descent is revealed. Yet, our data on Y-chromosome STRs variation demonstrate the clear differences between the South Siberian and Eastern European R1a1-lineages with the evolutionary ages compatible with divergence time between these two regional groups.

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