November 10, 2012
Iron Age Pazyryk mtDNA
The distinction between "west" and "east" in terms of genetics and geography was not always very concordant. East Eurasian mtDNA has been uncovered as far west as Ukraine, and West Eurasian mtDNA well to the east of Europe, in Siberia and eastern Central Asia. The former was extended in the boreal zone of north Eurasian hunter-gatherers, while the latter in the intermediate steppe zone. The results of this paper might suggest that the Europeoid zone extended only up to the Altai, but a previous study discovered mtDNA U5a in Lake Baikal, well to the east of this region. A temporal transect of a particular region, such as the one reported here may help elucidate not only the mixing of west/east types --which seems to be ancient across the northern parts of Eurasia-- but also the kinds of elements involved. For example, haplogroups K and J which are well-represented in the Iron Age results presented in this paper (especially the former), made their first appearance in the transition to the Iron Age in the Baraba forest-steppe zone to the west during the same time. The picture is still muddy, but a few patterns have begun to emerge: first U's, followed by T's during Andronovo horizon, followed by a wide assortment of lineages during the "Scythian" Iron Age. As I've written before, I strongly suspect that the last stratum originated in the area east of the Caspian sea, where the likely Proto-Indo-Iranian homeland existed, and where a segment of the BMAC population "went nomad" after the desiccation of their homeland.
Tracing the Origin of the East-West Population Admixture in the Altai Region (Central Asia)
Mercedes González-Ruiz et al.
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.