Archiver > GENEALOGY-DNA > 2010-11 > 1289227817

From: Mike W <>
Subject: [DNA] 2010 studies shed light on R-M269's relatively recent east towest migration
Date: Mon, 8 Nov 2010 08:50:17 -0600

2010 has been a big year for R-M269 (R1b1b2) studies. The Balaresque
and Myres studies have been examined and critiqued, but let's step
back and consider the significance of these two studies. The following
excerpts are from the opening statements of the abstracts.

1. 'A Predominantly Neolithic Origin for European Paternal Lineages'
by Balaresque et al:
"Haplogroup R1b1b2 is the commonest European Y-chromosomal lineage,
increasing in frequency from east to west, and carried by 110 million
European men. Previous studies suggested a Paleolithic origin, but
here we show that the geographical distribution of its microsatellite
diversity is best explained by spread from a single source in the Near
East via Anatolia during the Neolithic.

2. 'A major Y-chromosome haplogroup R1b Holocene era founder effect in
Central and Western Europe' by Myres et al:
"The phylogenetic relationships of numerous branches within the core
Y-chromosome haplogroup R-M207 support a West Asian origin of
haplogroup R1b, its initial differentiation there followed by a rapid
spread of one of its sub-clades carrying the M269 mutation to Europe."

There is a third 2010 study that, although not dedicated to R-M269,
provides supporting evidence for the same findings.

3, 'A map of human genome variation from population-scale sequencing'
by the 1000 Genomes Project Consortium:
"A striking pattern indicative of a recent rapid expansion specific to
haplogroup R1b was observed, consistent with the postulated Neolithic
origin of this haplogroup in Europe."

R-M269's highest frequencies are in Western Europe, particularly along
the Atlantic fringes, but including parts of Scandinavia. How can it
be that it may have originated to the east as far away as Southwest
Asia? At first it seems counter-intuitive, but highest current
frequency is not a good indicator of origin. There is a fourth earlier
study (2005) that explains the cause as the "wave surfing phenomenon."

4. 'The Fate of Mutations Surfing on the Wave of a Range Expansion' by
Klopfstein et al:
"...mutations arising in populations at the edge of a range expansion
can sometimes surf on the wave of advance and thus reach a larger
spatial distribution and a much higher frequency than would be
expected in stationary populations.....human expansions in Europe as
it should allow one to distinguish between mutations having spread
with Paleolithic or Neolithic expansions. By favoring the spread of
new mutations, a consequence of the surfing phenomenon is to increase
the rate of evolution of spatially expanding populations.... The
surfing phenomenon also includes a series of founder events, and it
leads to a continual increase of the allele frequency during the
successful spread of the new mutation."

Much of the above is actually not "new news." Amateur geneticists,
through projects like the "R-ht35 (M269+ P312- U106-) DNA Project" had
identified the probability of R-M269's true origin and direction of
expansion prior to the studies. For fear of omitting names, I won't
list them, but congratulations and great work!

Regards, Mike

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