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View Full Version : An environmental pattern to the origins of the differing R1b-R1a distributions?



alan
07-14-2013, 12:24 PM
I have no real confidence that this is a runner but I wanted to raise it for debate. Note that I am talking about the period 4500-2800BC, not later periods when all sorts of adaptions etc may have taken place. This also assumes a steppe or near-steppe location for R1b. This is an assumption of the thread and I dont want to debate that in itself.

My general suspicion is that R1a was located slightly more northerly on the edge of the forrest steppes. That makes sense both in terms of suggested origins of Yamnaya and also the swathe R1a later cut through the forrest steppes later in the Middle Dneiper-Fatyanovo-Abashevo sequence. We also know that there was at least an R1a element in corded ware which also seems to have cut a swathe through non-steppe land. It is also worth mentioning that the Middle Dnieper-Fatyanovo-Abashevo group have strong corded ware links as well as presumably a steppic element. You could say that the R1a-rich groups look like they may have been very adapted for that sort of environment.

R1b is trickier to make early observations on as it has a 'shattered' distribution in terms of its earlier clades. For the purposes I want to just focus on L23XL51 and M73 as they are the only substantial clades in and around the steppe zone. These clades probably can be said to not be well represented in the forrest steppe today. These clades are collectively present in reasonable amounts in the north Caucasus and central Asia and (in the case of L23XL51) also from Moldova west into the Balkans. There is a gap in the Ukraine steppe (the old Crimean Tatar Khanate) but it was essentially cleared of its population in the last 3 centuries and I do not believe that gap existed back in the copper age (or L23 folk must have taken to boats). Anyway, I think there is a hint that R1b may have been more used to the southern dryer steppes and of course the Caucasus interface touches an area of southern dry steppes. Whether this relates to an origin in Maykop's intrusions into the steppe fringes or is something older than that I am not sure.

Anyway, I think there is a suggestion of a pattern. I am of course trying to make a mountain out of a mole hill in terms of evidence but I still think its worth bringing up even if it is shot down. NOTE-again I am not wanting to discuss later groups like Andronovo when a lot of time had passed and adaption could have happened.