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From: Alan R <>
Subject: Re: [DNA] R-L21 possible areas of origin
Date: Mon, 11 Jan 2010 00:06:58 +0000 (GMT)


Anatole
 
I am basically in agreement that direction is not implied by L21 dating. However, the distributions and phylogeny of R1b clades together give some idea of the big picture R1b1b2 story in terms of direction of spread. 
 
As for beakers, the MRCA dates for R1b1b2 as they stand are too early to link with the beakers. Beakers seem to have developed almost as early as 5000 ybp in Iberia and to have completed their spread before 4000ybp. Otherwise, it would indeed be tempting to link the movement of R1b1b2 to beakers.  However, as well as beakers being too old for these MRCA dates, current dating strongly favours Iberia as the point of origin of a west to north or east movement NOT the south-western stepping stone of an east to west movement originating in the east.  Personally though I think the beaker culture interpretation may continue to radically change as new dating happens.  I wouldn't be surprised if some day an east to west story for beakers is reverted to! 
 
When I said of the idea of an early Neolithic spread for R1b1b2 that "this demands the
age of R1b1b2 to be over twice as old as the MRCA calculations", I only meant that IF that stance was taken then the problem is the early Neolithic is twice as old as the MRCA calculations.  I was not saying who was right and who was wrong.  I was just saying that the MRCA dates and an early Neolithic R1b1b2 spread are incompatible by a factor of two.
 
I was also not eliminating other haplogroups.  I was only going through the problems of each period one by one giving a critique of each period as that of the entry of R1b1b2 into the west.  Other clades were simply not the topic of my discussion.  

When I noted an incompatibility of the proposed MRCA dates c. 1500BC with the archaeological evidence, I meant that very few archaeologists (probably none) see much evidence around 1500BC or after it of a population change of the sort that would lead to R1b1b2's current dominance.  I was primarily thinking of the isles as an example of an area with high R1b1b2 which requires an explanation for its presence.

cheers
Alan
 
Anatole said

You have placed a lengthy piece here, however, it is not clear what do you
suggest, offer, state. Dating by itself does not give "direction of spread".
A serious of dating can do. The fact that R-L21 was originated 3575 years
ago does not give is a direction of their movement. However, the dating of
R1b1b2 as 5200 ybp in the Middle East, 3800 ybp in Algeria, 3700 ybp in
Iberia, and 3600 ybp on the Isles can give a hint. Then it also can give a
hint who the Beakers were, since they apparently had spread from Iberia, and
in about the same times. So why are you saying that it is "impossible to
correlate with archaeological evidence"? What "evidence" you want to see?
What size of a "major population change" do you want to see? Who told you
that the "population movement" in the early Neolithic - "this demands the
age of R1b1b2 to be over twice as old as the MRCA calculations" - was
necessarily R1b1b2? Why not R1a1? Why not I1? I2? What is a root of your
logic that wants to see ONLY R1b1b2 in early Neolithic? Any evidence for
this?


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