Complete Mitochondrial DNA Analysis of Eastern Eurasian Haplogroups Rarely Found in Populations of Northern Asia and Eastern Europe

With the aim of uncovering all of the most basal variation in the northern Asian mitochondrial DNA (mtDNA) haplogroups, we have analyzed mtDNA control region and coding region sequence variation in 98 Altaian Kazakhs from southern Siberia and 149 Barghuts from Inner Mongolia, China. Both populations exhibit the prevalence of eastern Eurasian lineages accounting for 91.9% in Barghuts and 60.2% in Altaian Kazakhs. The strong affinity of Altaian Kazakhs and populations of northern and central Asia has been revealed, reflecting both influences of central Asian inhabitants and essential genetic interaction with the Altai region indigenous populations. Statistical analyses data demonstrate a close positioning of all Mongolic-speaking populations (Mongolians, Buryats, Khamnigans, Kalmyks as well as Barghuts studied here) and Turkic-speaking Sojots, thus suggesting their origin from a common maternal ancestral gene pool. In order to achieve a thorough coverage of DNA lineages revealed in the northern Asian matrilineal gene pool, we have completely sequenced the mtDNA of 55 samples representing haplogroups R11b, B4, B5, F2, M9, M10, M11, M13, N9a and R9c1, which were pinpointed from a massive collection (over 5000 individuals) of northern and eastern Asian, as well as European control region mtDNA sequences. Applying the newly updated mtDNA tree to the previously reported northern Asian and eastern Asian mtDNA data sets has resolved the status of the poorly classified mtDNA types and allowed us to obtain the coalescence age estimates of the nodes of interest using different calibrated rates. Our findings confirm our previous conclusion that northern Asian maternal gene pool consists of predominantly post-LGM components of eastern Asian ancestry, though some genetic lineages may have a pre-LGM/LGM origin.本研究旨在揭示北亚线粒体DNA（mtDNA）单倍群的最基础遗传变异，我们对来自西伯利亚南部的98名阿尔泰哈萨克族个体与中国内蒙古的149名巴尔虎人的mtDNA控制区及编码区的序列变异进行了分析。两类人群均呈现欧亚东部谱系的高频分布，其中巴尔虎人中该类谱系占比达91.9%，阿尔泰哈萨克族中则为60.2%。研究发现阿尔泰哈萨克族与北亚、中亚人群具有高度遗传亲缘关系，这既体现了中亚原住民的遗传影响，也反映出其与阿尔泰地区土著人群的关键遗传互作。统计学分析结果显示，所有蒙古语族人群（蒙古人、布里亚特人、哈米尼干人、卡尔梅克人以及本研究中的巴尔虎人）与说突厥语的索约特人聚类关系紧密，提示其源自共同的母系祖先基因库。为全面覆盖北亚母系基因库中已发现的DNA谱系，我们从涵盖北亚、东亚及欧洲的超过5000份mtDNA控制区序列的大规模样本库中，筛选出代表R11b、B4、B5、F2、M9、M10、M11、M13、N9a及R9c1单倍群的55份样本，并对其mtDNA进行了全序列测定。将最新更新的mtDNA系统树应用于此前已发表的北亚及东亚mtDNA数据集，不仅厘清了此前分类不明的mtDNA类型的分类地位，还使我们能够通过不同的校准速率估算目标节点的溯祖年龄。本研究结果证实了我们此前的结论：北亚母系基因池主要由末次盛冰期（Last Glacial Maximum, LGM）后的东亚血统组分构成，不过部分遗传谱系可能起源于末次盛冰期前或末次盛冰期阶段。