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Saturday, September 20, 2008

Pyrenean Y-DNA


Take a look at
Dienekes' Anthropology Blog: 'Y chromosomes from the Pyrenees'. Based on López-Parra et al. 2008 (behind a paywall).

Most interesting is this map of haplogroup frequencies, showing that R1b1b2a2c (M153, light blue) is most common among Basques but very rare among other populations (it has also been detected in minimal ammounts in Spain and among Latin Americans), while R1b1b2a2d (M167, dark blue) , while also found among Basques, is much more common among other Pyrenean populations, notably Aranese (c. 50%), being found among other Iberians at small apportions too.
This R1b subclade (M167) is known (from other studies) to have been found at rates of 12% among Catalans, 5% among the French (no known data on Gascons, of whom Aranese are a subpopulation), 2% among other Iberians and occasional occurrences in other European locations. I am seriously intrigued about R-M167 frequency among Gascons and Occitans, because the very high apportion among Aranese people and the relatively high presence on all-France samples (as well as NW Iberians) strongly suggests it is rather prevalent through all the prehistoric Franco-Cantabrian region.

Other results refer to haplogroup I. The clade is somewhat common though the Pyrenees and I2a2 (M26, most frequent in Sardinia) appears particularly significative in two locations: "Jacetania" (medieval Aragon county) and Cerdanya (in old Catalonia), with less important presence in other localities and in the rest of Iberia. I(xI2a2) is also somewhat important but it is not clear if it may be I2a1 ("Balcanic"), I2b ("NW mainland European") or I1 ("Scandinavian"). My guess is that, as it mostly associated to I2a2, it will be mostly I2a1 but the matter is not fully clear. Western Basques appear low in both I clades but they are relevant among High Navarrese (Cinco Villas).

The other detached piece of cake is described generically as Neolithic haplogroups. Considering that R1a (very rare anyhow) is assimilated in the R+I cake share as supposedly non-Neolithic, I understand it means haplogroups G, J and E. These ake a significative fraction of the Iberian cake (like 30%) but are less important among Pyrenean peoples (except Alt Urgell). Anyhow, again the study fails to make a distinction between the three haplogroups, that surely had different origins: J arriving from the Eastern Mediterranean, E almost exclusively from North Africa (and surely the most important "Neolithic clade" in Iberia) and G being still an unsolved mystery (though an Eastern Med Neolithic source is likely).

2 comments:

X. d'Iber said...

Interestingly enough, within the Iberian context, the High Navarrese apppear as distinctive from the Basques.

Maju said...

Why do you say that? I really do not see it.

The only Navarrese cake is that of "Cinco Villas", which is the High Bidasoa, not far from San Sebastian (Bera and other semi-rural towns). And the difference with the Western Basque urban sample is not apparent at all. Of course, one should always expect *some* difference among any two different samples, even in the same town.

The only difference I can spot is that the Navarrese sample lacks the "Neolithic" clades (probably all J2) that are apparent at low levels among urban Western Basques. Instead they appear to have a slightly high apportion of haplogroup I. Both groups are the only ones to share the Basque/Gascon lineage M153, very rare elsewhere and both are learly dominated by R1b overall, something not so apparent among Spaniards, who appear to have like 30-40% of their Y-DNA of non-local origin (North Africa, Eastern Med.)

What is interesting is the other R1b subclade (M167) that appears also to be original from Paleolithic peoples but with a more Eastern distribution (strong specially in Catalonia, but also present among Gascons and in the eastern half of Iberia).

I also found surprising that Jaca appears so distinct from Basques, totally in the Eastern Pyrenean context. But that would probably be less apparent if Gascons had been sampled anyhow.