Tarim basin mummies represents a group of ancient mysterious populations that lived in north west of China

 Tarim basin mummies represents a group of ancient mysterious populations that lived in north west of China. They were pastoralists ( ~2000-100BC), and had a peculiar culture. Mummification was natural rather than hand made. The most surprising are their phenotypes, which was predominantly Caucasoid ( or Europoid ). Some mummies from later periods had Mongoloid admixture but they were found from more eastern regions. See the map for the location.

Mummies from the site Xiaohe were tested and it turn out that they had predominantly ANE autosomes. ANE stands for "Ancient North Eurasians". An abbreviation for a large extinct Caucasoid race population that lived in Paleolithic Central Asia and Siberia, from the Ural river to Amur river, except the Far East coastal regions of Pacific, before the expansion of Mongoloid East Asians. ANE people had predominantly the Q1 haplogroup but occasionally R1 was found among them also.

Those tested Xiaohe mummies had R1b from a basal branch so it is important to localise their initial homeland. The model below shows that the most preferred source of ancestry for Xiahoe mummies is from Tyumen HG which is from Kazakh- Russian border. While the second most important source is from Tajikistan hunters-gatherers marked as TTK. They don't have any East Asian ancestry, besides what is already is present in Tyumen HG which is linked to so called Western Siberian hunter gatherers, WSHG. This data means that the most likely homeland of Tarim mummies was in Central Asia.

Apparently in Central Asia they learned the pastoralism from more southern farmers and moved to Tarim basin. Common origins with an R1b found in Uzbekistan farmers (BMAC) also supports the idea that they were from Central Asia rather than Eastern Siberia.

Their ethnicity is unknown but they were not Indo-European for sure. IE Tocharians settled there with Yamnaya derived cultures creating the local Chemurchek culture which was just in the north of Xiahoe. The Tocharian autosomes are quite different but ironically Tocharians also had the R1b haplogroup from another branch.

In conclusion the theory positing the R1 homeland in East Siberia do not find support by this data.

The more realistic assumption is the Eastern European homeland of R1 were the highest diversity of ancient R1 branches is found. Another argument for Europe is that EHG has a strong association with R1. Note that Tyumen HG himself do have some amount of EHG, so the presence of R1b there do not contradict to this claim. The presence of old R1b in Paleolithic Italy in WHG context also supports the Eastern Europe as the place were R1 bifurcated and differentiated into many branches. As for the common ancestor of R1 and R2 the current best candidate is the Central Asia, Eastern Caspian sea basin.

More data will clarify this question in the future I have the feeling that we will hear some surprising news about the ANE and R1 origins stories in the coming years.