Ancient DNA evidence of major population movements from West Eurasia all the way to China just after the Neolithic is really piling up now. Here's an open access article from BMC Biology that focuses on a 4,000-year-old burial site in the Taklamakan desert.
Besides the East Eurasian lineage, two West Eurasian mtDNA haplogroups H and K were found among the Xiaohe people. H lineage is the most common mtDNAhaplogroup in West Eurasia , but haplogroup H with a 16260T was shared by only nine modern people in Genbank, including one Italian, one German, one Hungarian,one Portuguese, one Icelander and four English people. Haplogroup K, a western Eurasian–specific haplogroup, is mainly distributed in Europe, central Asia, and Iran [20, 21]. However, haplogroup K with 16134T, found in the Xiaohe people, has not been found in modern people to our knowledge.
Regarding the Y chromosomal DNA analyses, the seven males identified all belonged to haplogroup R1a1a. It is most frequently found in Eastern Europe, South Asia and Siberia. In contrast, it is relatively uncommon in Middle Easterners and rare in East Asian [22-24]. It is thought to be a trace of the migration events of early Indo-European [38-39]. The presence of haplogroup R1a1a in the ancient Xiaohe people implies that the parental ancestry of the Xiaohe people originated from somewhere in Siberia or Europe, which is consistent with the origin of maternal ancestry.
Chunxiang Li et al., Evidence that a West-East admixed population lived in the Tarim Basin as early as the early Bronze Age, BMC Biology 2010, 8:15, doi:10.1186/1741-7007-8-15