More ancient mtDNA from Central Asia has been tested, ranging from 7000 to 1500 years ago.
In the Tarim Basin, 4000-year old remains belonged to both East Asian (C, D, F, G, M7, Z) and European haplogroups (
H, K, U2e, U4, U5, W).
Interestingly, haplogroup U5a was found in Mongolia and southern Siberia (peri-Baikal region), some specimen as early as 7000 years ago, i.e. slightly before the presumed Indo-European expansion (following the domestication of the horse in the Volga-Ural region circa 6000 years ago).
Haplogroups
H5a, H6, HV, I, K, T1, T3, T4, U2, U4, and U5a1 were
found in the modern Xiongnu people around Lake Baikal, besides North-East Asian haplogroups C, F1b, G2a, N9a, and Z. This much greater diversity of European lineages confirms that bigger scale migrations took place from the Pontic-Caspian steppe to the Baikal region after 6000 years ago.
European haplogroups from other sites in ancient Siberia, Kazakhstan and Mongolia include
HV, H, I, J1, K, T, U1, U2, U4, U5 and W. The presence of J1 and U1, usually associated with the Middle East, is moderately surprising. It is rare enough to invalidate a Middle-Eastern origin of the Indo-Europeans, but suggests that the Indo-Europeans were indeed neighbours and have taken Middle-Eastern wives occasionally.
The Y-DNA of the men tested above was constantly R1a1.
What's interesting here is the absence of R1b and of mtDNA U3 and X, which I have identified as the maternal equivalent of R1b. R1b now makes up about 20% of the Uighur male lineages, and U3 and X2 were both found in modern inhabitants of the Tarim Basin. It reinforces the evidence that R1b came along with U3 and X2. The question is when ? If 4,000-year-old Tarim mummies were all R1a1, it means that fair hair and tartan-pattern clothes, both associated with the Indo-Europeans, came from the R1a1 branch of the Indo-European rather than the southern R1b branch.