Post by Admin on Feb 12, 2024 21:11:29 GMT
Table 3.Age Estimates of mtDNA Haplogroups U4, H, HV0a, and V with ρ and from Two Different Molecular Clocks.
ρ Estimates (95% confidence interval), in ka ago
Haplogroup Sample Size Complete Genome Synonymous Positions
U4 61 16.5 (10.7 to 22.4) 17.3 (5.6 to 29.1)
U4a 44 13.1 (7.8 to 18.5) 6.8 (4.0 to 9.5)
U4a1 14 9.6 (5.3 to 14.1) 11.3 (4.3 to 18.2)
U4a2 29 7.8 (4.7 to 11.0) 4.1 (1.5 to 6.7)
U4b 6 16.2 (7.8 to 24.9) 21.0 (5.1 to 36.9)
U4d 7 12.6 (5.6 to 19.8) 15.7 (2.2 to 29.3)
HV0a 40 14.4 (7.0 to 22.0) 14.6 (−0.1 to 30.3)
V 39 11.8 (6.5 to 17.2) 6.9 (2.1 to 11.6)
V1a 17 7.9 (2.5 to 13.5) 2.8 (−0.3 to 5.8)
V1a1a1 6 0.85 (−0.4 to 2.1) 0
V3a 6 4.8 (0.02 to 9.7) 7.9 (−0.5 to 21.0)
H 16 17.9 (13.6 to 22.3) 16.2 (9.4 to 23.0)
Previous studies have shown that the Volga-Ural region has an important role in the peopling of the northeast of Europe. It has been found that some Saami and Finnish mtDNA lineages (such as haplogroups U5b1b1, V, and Z1a) shared a common ancestor with lineages from the Volga-Ural region (Tambets et al. 2004; Achilli et al. 2005; Ingman and Gyllensten 2007). The divergence time for the Saami and Finnish haplogroup V sequences was estimated as 7.6 ka ago and for U5b1b1 as 5.5–6.6 ka ago (Ingman and Gyllensten 2007). Much lower age of haplogroup Z1a (2.7 ka ago) suggests also a more recent contribution of people from the Volga-Ural region to the Saami gene pool. In the present study, we sequenced five mitochondrial genomes of Tatars belonging to haplogroup HV0, so these additional data appear to be useful for molecular dating of haplogroup V. We analyzed 32 published haplogroup V mitochondrial genomes from populations of Finns and Saami (Finnilä et al. 2001; Ingman and Gyllensten 2007) and three novel genomes from populations of Russians and Czechs (EU567453-EU567455) (supplementary fig. S3, Supplementary Material online). As a result, we have found that three mtDNAs of Tatars fall into subcluster V1a that is very frequent among Finns (Finnilä et al. 2001). It is noteworthy that Tatars and Finns share mtDNAs from this subcluster on a large time span—from 7.9 and 2.8 ka ago (for complete genome and synonymous rates, respectively) for subcluster V1a to 0.85 ka ago and even less (for complete genome and synonymous rates) for small subcluster V1a1a1 (table 3). In addition, analysis of subcluster V3a demonstrates that divergence between Russian/Finnish mtDNAs is estimated as 4.8 and 7.9 ka ago (for complete genome and synonymous rates, respectively).
Based on complete mtDNA variation of eastern Europeans (for 40 mitochondrial genomes from populations of Finns, Saami, Tatars, Russians, and Czechs), haplogroup HV0a dates to ∼14.5 ka ago, fitting the time of expansion from European glacial refuge zones (the Franco-Cantabrian, Balkan, and Ukrainian ones) (table 3). Meanwhile, haplogroup V (39 genomes of eastern Europeans) dates to 11.8 ka ago for complete genome rate and to 6.9 ka ago for synonymous rate, that is, somewhat less than previously reported dating results for haplogroup V in Europe—13.7 (12.1–15.2) ka ago for complete genome rate and 12.2 (10.0–14.3) ka ago for synonymous rate (Soares et al. 2009).
Conclusions
In summation, mitochondrial gene pool of the Volga Tatars is characterized by high level of diversity and it can be seen as composite of both western and eastern Eurasian mtDNA haplogroups. In the Volga Tatars, there are no specific mtDNA clusters of eastern Asian origin, allowing us to suggest early presence of eastern Asians/Siberians in the Volga River basin. On the contrary, western Eurasian mtDNA lineages appear to be very diverse. The age of haplogroups U4 and HV0a, which is less than 18.0 ka ago, suggests re-expansion of eastern Europeans soon after the Last Glacial Maximum, as does the age of haplogroup H, which dates to ∼17.0 ka ago based on mtDNA diversity in Tatars (table 3). Much more detailed information on mtDNA diversification process in eastern Europe will be obtained after considerable enlargement of database of complete mitochondrial genomes created in the present study.
We are grateful to Nikolay Eltsov for help in this study. The study was supported by grants from the Program of Presidium of Russian Academy of Sciences “Biodiversity” (09-I-P23-10) and the Russian Foundation for Basic Research (07-04-00445).