Semino et al thought the the forefather of all R1a1s was probably born in the Ukraine during the Last Glacial Maximum about 15,000 years ago. Spencer Wells has put forward the theory that the subsequent spread of haplogroup R1a1 across Eurasia may have been connected to the domestication of the horse about 5000 years ago ( Kurgan culture). The range of the distribution of R1a1 across Eurasia can be seen as the light blue colored group in the map on the third page of Wells' Eurasian Heartland paper. If Wells' theory is correct, the R1a1 haplogroup may have ridden on horseback from one end of Eurasia to the other. So the association of this haplogroup with the Vikings is, in truth, little more than a minor footnote in the history of the R1a1 group.

There may be two regional patterns associated with the STRs seen among the R1a1s:

Passarino et al saw DYS19=15 and YCAIIa,b=19,21 as being specific to the R1a1s in Western Europe, while Eastern European R1a1s typically had DYS19=16 and YCAIIa,b=19,23. This latter pattern is also seen in some Western Europe R1a1s - but the earlier pattern is almost never seen in Eastern European R1a1s.

Ploski et al saw a pattern in the STRs of the R1a1s that seemed to be specific to the region around Poland. Another recent paper claims that this haplotype is fifteen times more common in Poland than in the rest of Europe. The pattern is common enough in that area that two versions of it appear among the 30 most common haplotypes in the European YSTR.org database. Those two haplotypes can be seen here. More information is available here.

The graphs below show a comparison between the R1a1 results from Turkey with those seen by Helagason for HG3s in Iceland. As can be seen, the two sets of results have virtually identical allele frequency graphs - except for DYS19. Qamar's study of Y chromosomes in Pakistan found a modal haplotype for HG3 that differed by only a single step at DYS389ii from that seen for R1a1 in Turkey.

The distribution of R1a1 in Europe can be seen as the group colored in purple on the map on the second page of Semino's paper on European Y chromosomes.

There are presently no R1a1 sub-groups worth SNP testing. R1a1c (M87) has only been seen in Central Asia/Siberia, and R1a1a (M56) and R1a1b (M157) have only been seen a single time each (in India/Pakistan and Central Asia/Siberia).