May 11, 2010

Complex picture of R-M269 dispersal

A very interesting abstract from the HAPLOID DNA MARKERS IN FORENSIC GENETICS workshop that took place in April. I will scour the abstract volume (pdf) for other interesting pieces of research, but I wanted to give an early heads-up on this abstract, given the recent interest on this haplogroup, and the controversy regarding its origin. It is also exciting to see the issue of the mutation rate finally addressed, I hope the authors take my side on the debate.

We'll have to wait and see what the authors propose when their paper is actually published, but I am guessing that my post on Haplotype outliers and Y-chromosome age estimation will be vindicated. Therein, I argued that Y-STR age estimation sometimes leads to young ages if "relics of a bygone age" are not identified, and the age estimation is dominated by the dominant (and more recent) expansion. As far as I can intuit from the abstract, the authors seem to propose such a model, in which an expanding Neolithic R-M269 population interacted with pre-existing European R-M269. Let's hope the details surface soon.

Increased Resolution Within Y-Chromosome Haplogroup R1b M269 Sheds Light On The Neolithic Transition In Europe

George Busby et al.

Early studies on classical polymorphisms have largely been vindicated by the growing tome of information on the genetic structure of European populations, with mtDNA, Y-Chromosome and autosomal markers all combining to give a fundamental pattern of migration from the East. The processes behind this pattern are however, less clear, particularly with regard to uniparental markers. Much debate still rages about how best to use Y and mtDNA to date particular historical movements, or indeed if it is appropriate at all. For example, whilst some progress has been made recently in calibrating the mtDNA clock, the selection of a mutation rate with which to date the Y-Chromosome is contentious, as the two most favoured values can give dates that differ by a factor of three. In order to address this we have investigated the sub-lineages of the common European haplogroup R1b-M269. This haplogroup has been shown to be clinal in Europe, and more recently has been posited to be the result of the Neolithic expansion from the Near East. Here, we use newly characterised SNPs downstream of M269 to produce a refined picture of the haplogroup in Europe, and further show that the diversity of this lineage cannot be entirely attributed to Neolithic migration out of Anatolia. We use simple coalescent simulations to estimate an absolute lower bound for the age of the sub-haplogoups. Rather than originating with the farmers from the East, we suggest that the sub-structure of R1b-M269 visible in Europe today, and thus the great majority of European paternal ancestry, is the result of the interaction between the Neolithic wave of expansion and populations of early Europeans already present in the path of the wave.


McG said...

I had not read your December 2008 memo before. I think you are right on! This is especially true of R-L21. My Ysearch is z5hg3. From the ordinary R-L21, I have a GD of 20 to 30. From people like myself it is closer to 30 to 40. I believe R-L21 was born near the low countries, possibly even doggerland? The modal values of R-L21 simply represent the dominant group of haplotypes, not the "outliers". How would you go about estimating TMRCA of outliers?

Dienekes said...

If you posted a comment on this yesterday it may have been lost in a moderation accident. Unfortunately I have had to start moderating comments because of the appearance of certain trolls, but I deleted a bunch of comments by accident when I meant to delete a single one. So, if it's not too much trouble, post your comment again.

Andrew Oh-Willeke said...

Shit happens. The time you've devoted to keeping your blog troll free is appreciated in any case, so thank you for your posts and for your moderation. It can be a pain.

Just please stay away from the stock market, where fat fingers are supposed to be capable of erasing 10% of market value of the entire economy in mere minutes. ;)

Unknown said...

what Dienekesa,

you like the theory of
expanding Neolithic R-M269 population interacted with pre-existing European R-M269.

You don't like in India

expanding Neolithic R1a population interacted with pre-existing Indian R*

Gioiello said...

I think we all like truth and are searching for it. For me, and I think also for Dienekes, it is clear that there have been many waves of hg. R: India has an ancient stratum of R1a and probably a recent one come with Indo-Europeans. For us the fact that scholars begin to recognize that R1b1* and subclades were in Western and Southern Europe before what are thinking Vizachero and others is already something. We'll see from when. My bet is before the Younger Dryas.