Re: [tied] Recent Male-Mediated Gene Flow over a Linguistic Barrier

--- In cybalist@yahoogroups.com, "Brian M. Scott" <BMScott@...> wrote:

> Here's the summary:

> We have examined the worldwide distribution of a
> Y-chromosomal base-substitution polymorphism, the T/C
> transition at SRY-2627, where the T allele defines
> haplogroup 22; sequencing of primate homologues shows that
> the ancestral state cannot be determined unambiguously but
> is probably the C allele. Of 1,191 human Y chromosomes
> analyzed, 33 belong to haplogroup 22. Twenty-nine come
> from Iberia, and the highest frequencies are in Basques
> (11%; n = 117) and Catalans (22%; n = 32).

Given the proportions of 13 out of 117 for the Basques and 7 out of 32
for the Catalans, it would seem that the flow was from Catalans to
Basques, but the evidence as to direction is far from overwhelming.

> Microsatellite
> and minisatellite (MSY1) diversity analysis shows that
> non-Iberian haplogroup-22 chromosomes are not
> significantly different from Iberian ones. The simplest
> interpretation of these data is that haplogroup 22 arose
> in Iberia and that non-Iberian cases reflect Iberian
> emigrants. Several different methods were used to date the
> origin of the polymorphism: microsatellite data gave ages
> of 1,650, 2,700, 3,100, or 3,450 years, and MSY1 gave ages
> of 1,000, 2,300, or 2,650 years, although 95% confidence
> intervals on all of these figures are wide. The age of the
> split between Basque and Catalan haplogroup-22 chromosomes
> was calculated as only 20% of the age of the lineage as a
> whole.

So is Haplogroup-22 about 12,500 years old, or is the Catalan-Basque
haplogroup-22 split about 500 years old? 'About' covers a very wide
range.

> This study thus provides evidence for direct or
> indirect gene flow over the substantial linguistic barrier
> between the Indo-European and non–Indo-European–speaking
> populations of the Catalans and the Basques, during the
> past few thousand years.

If the older dating is what is meant, then we are talking of a flow
between the non-IE Iberes and the Basques! On the younger
interpretation, we are talking of a mixing of populations possibly
associated with the Reconquista.

> Carl's comment appears to be a non sequitur.

And the introduction of 'Indo-European' into the paper seems to be
sensationalist.

Richard.