[radikal]

It is likely that M173 arose initially in Central Asia, and that M173-carrying subpopulations migrated westward into Europe soon thereafter. The extremely high frequency of this haplotype in Western Europe is probably the result of drift, consistent with an inferred population bottleneck during the Last Glacial Maximum (4, 17).

The American descendant of M45, defined by the marker M3, may be as little as 2,000 years old (10); this finding, as well as the fact that it is not found in Central Asia or Siberia, suggests that the expansion of this haplotype occurred entirely within the Americas. An assessment of the upper limit to the date of entry of humans into the Americas therefore awaits the identification of further markers on the M45 lineage that are ancestral to M3 and are found in both Central Asia and America. What seems clear, though, is that an ancient M45-containing population living in Central Asia was the source of much modern European and Native American Y-chromosome diversity.

http://www.pubmedcentral.gov/article...medid=11526236