Prehistoric Hunter-Gatherers of the Baikal Region, Siberia: Bioarchaeological Studies of Past Life Ways

6. Genetic Diversity in Native Siberians: Implications for the Prehistoric Settlement of the Cis-Baikal Region

Genetic Diversity in Native Siberians: Implications for the Prehistoric Settlement of the Cis-Baikal Region Theodore G. Schurr, Ludmilla P. Osipova, Sergey I. Zhadanov, and Matthew C. Dulik Since 1992 genetic research has greatly illuminated the history of and biological relationships among indigenous Siberian populations. Studies employing the maternally inherited mitochondrial DNA (mtDNA) and the paternally inherited Y-chromosome (NRY) have provided new information about the origins and patterns of dispersal of a variety of the native populations that inhabit this part of northern Eurasia (Fig. 6.1). By analyzing variation in these two genomic components, researchers have been able to more clearly associate the patterns of genetic diversity and geographic distribution of these two kinds of haplotypes and, hence, obtain a much better picture of female and male genetic histories in Siberia. Unlikemostpopulationsinotherpartsoftheworld,nativeSiberiangroups have remained relatively isolated from other groups in northern Eurasia. This geographic isolation has given rise to unusual haplotypes and patterns of recombination at major histocompatibility loci antigen (HLA) loci (Grahovac et al. 1998). Similarly, because of their relatively small effective population sizes (and perhaps because of an ancient common origin for many of them), one finds extensive linkage disequilibrium in the genomes of indigenous Siberian groups (Kaessmann et al. 2002), as well as evidence of genetic drift affecting patterns of mtDNA haplotype diversity (Schurr et al. 1999; Derbeneva et al. 2002a and b; Derenko et al. 2003; Schurr and Wallace 2003). In addition , the high level of Y-chromosome differentiation in these populations has been interpreted as the genetic signature of a boreal hunter-gatherer way of life (Karafet et al. 2002). Furthermore, through broad surveys of molecular genet- ‹ 6 › 122 T.G. Schurr, L.P. Osipova, S.I. Zhadanov, and M.C. Dulik ic variation in these Siberian groups, we have delineated regional patterns of cultural and biological diversity in northern Eurasia that reflect longstanding processes of interaction between groups within those areas (Schurr et al. 1999; Karafet et al. 2001; Schurr and Wallace 2003) (Fig. 6.2). Patterns of biological diversity in Siberia are likely attributable to a number of factors. The first is the Pleistocene dispersal of human populations into the region after their departure from East Africa (Quintana-Murci et al. 1999; Underhill et al. 2000; Zhivotovsky, Rosenberg, and Feldman 2003). Arriving in northern Eurasia approximately 40–45 kya, these populations brought with them a specific subset of mtDNA (M and N) and NRY (e.g., C, DE, F) lineages from which most of the known lineages in the region evolved (Macaulay et al. 1999; Kivisild et al. 2002; Underhill et al. 2000; Y-Chromosome Consortium 2002). Once human groups settled in Central and East Asia, they developed distinctive gene pools that subsequently mixed, around 20–35 kya, in the region now represented by Mongolia and northern China (Su et al. 1999; Karafet et al. 2001; Zerjal et al. 2002). With the onset of the last glacial maximum (LGM) (25–14 kya), human groups living in northern Eurasia were pushed into more southerly regions, a process that may have led to the mixing of formerly distinct groups during this time (Forster 2004). After the LGM, during the Late Pleistocene and early Holocene, there 6.1. Indigenous Siberian and East Asian populations compared in this analysis. Genetic Diversity in Native Siberians 123 was a re-expansion of human groups into the north (Forster 2004). Included in these Neolithic re-expansions was the emergence and dispersal of Tungusic populations, perhaps in association with reindeer herding (e.g., Simchenko 1976), which may be related to the distribution of mtDNA haplogroup Z and NRY haplogroup N3 across northern Eurasia (Schurr et al. 1999; Karafet et al. 2001; Lell et al. 2002; Schurr 2004). Much later, between 1,000 and 1,200 years ago, Mongolic- and Turkic-speaking populations began expanding across Central Asia and East Siberia (Derenko et al. 2001; Pakendorf et al. 2003; Zerjal et al. 2003; Quintana-Murci et al. 2004). Most recently, the Russian conquest of Siberia led to changing population distributions through the region because of trade, war, disease, and forcible relocation by Tsarist and Soviet governments (Forsyth 1992; Lincoln 1994; Slezkine 1994). This series of prehistoric population movements and later political conquest have created a complex picture of genetic variation. It is the task of molecular anthropologists to reconstruct the timing and nature of the processes that generated this diversity. 6.2. mtDNA haplogroup frequencies and regions...