May 08, 2009

Basques are not a genetic isolate


This paper shows that Basques, who are viewed by some as a relatively isolated remnant of the European Paleolithic population, do not in fact show any signs of being a genetic isolate, having similar levels of heterozygosity, i.e., tendency to have different alleles in any particular locus, and linkage disequilibrium, i.e, the tendency of alleles in big blocks of DNA to be inherited together.

The MDS plot of the Fst distances is also quite interesting, showing Catalans, Extremadura, Basques, and Andalusians on the left, and Moroccans and Saharans on the right. As the authors note:
The MDS plot shows that genetic variation can be described with a single component, namely, Iberian vs North African populations (note the huge difference in scale between components 1 and 2), and Basques are not differentiated from other Iberian populations.


European Journal of Human Genetics doi:10.1038/ejhg.2009.69

Isolated populations as treasure troves in genetic epidemiology: the case of the Basques

Paolo Garagnani et al.

Abstract

The Basques are a culturally isolated population, living across the western border between France and Spain and speaking a non-Indo-European language. They show outlier allele frequencies in the ABO, RH, and HLA loci. To test whether Basques are a genetic isolate with the features that would make them good candidates in genetic association studies, we genotyped 123 SNPs in a 1-Mb region in chromosome 22 in Basque samples from France and Spain, as well as in samples from northern and southern Spain, and in three North African samples. Both Basque samples showed similar levels of heterozygosity to the other populations, and the decay of linkage disequilibrium with physical distance was not different between Basques and non-Basques. Thus, Basques do not show the genetic properties expected in population isolates.

Link

33 comments:

Maju said...

The Basques are a culturally isolated population...Nah. It's the rest of the world who are a culturally isolated population. When they learn Basque language, they won't be anymore. :P

[Basques] do not in fact show any signs of being a genetic isolate....

Exactly. There's been people claiming here that Basques are "inbred" and similar stuff. This hopefully will make them shut up.

Basques are just like their neighbours (mutatis mutandi) and have never been particularly isolated, just that the Mediterranean and Indoeruopean influences that dot them, are virtually absent among Basques and Gascons (and to a lesser extent in other West European peoples like Atlantic Celts).

onur said...

just that the MediterraneanYou mean the central/eastern Mediterranean?

Maju said...

Mediterrean, you know: from the sea and the lands that border it: Egyptians, Greeks, Moroccans... we even use that term for Andalusians and the like at times. Not your usual Coon, I guess but that's how we use the term Mediterranean here.

For us, in West Eurasia, it is Mediterraneans (café-au-lait), Nordics (watered down milk) and the ones like us (standard white). Coon wasn't Basque obviously. :P

onur said...

By your definition, I am a Mediterranean too (I am an ethnic Turk). BTW, an ethnic Turkish friend of mine who is from eastern Turkey looks very much like you. Maybe you are from those Basques influenced by Mediterranean input. :D

Maju said...

Yah, you are Mediterranean by geography but if your skin is not tanned under low sun-exposure conditions, I would not say you're "Mediterranean" by type. I would not call Saddam Hussein "Mediterranean" by this standard but I'd call it to Hosni Mubarak or Ahmadinejad (though the later looks more like Indian, right?) or Penelope Cruz (but not to Almodóvar who is very paleish in spite of having black curled hair).

Anyhow, fyi, I am not any purebreed Basque: at least 40% of my ancestry is foreign (northern Spanish and northern Italian, though some of the northern Spanish and the Basque ancestry is hard to trace this or that side of the historical Basque area). I am anyhow then only black haired one among my syblings but the blondiness in my family is as much Basque as it is Italian (both my grandfathers were blue eyed blonds, whatever that means). But while there's a relatively high ammoun of blonds among Basques, most are brunette, indeed. The always-tanned Mediterranean type is very rare though, except in the Ebro Valley (a well known area of Mediterranean admixture at the arrival of Neolithic), where they are somewhat more common.

IMO, my type (or that of your friend, I'm guessing) is the basic Caucasoid type (at least in regard to pygmentation), though it can be argued, I guess that the Mediterranean, always-tanned, type is older maybe and that the other is derived. The extreme Nordic (blond, hard or impossible to tan) type is marginal and must have evolved within the process of colonization of the far north, when tanning was not anymore of any use. But a less extrem blond ("fair") type (lighter than my complexion but, well, like my blond syblings) may well have existed since very long ago. I doubt this is any way too recent developement.

Also, based on the quite frequent existence of hair blondism among tropical Eurasians (Australian Aborigines, Melanesians), I'd argue thate the genes leading to blond hair were already in the Eurasian genetic pool (possibly at very low levels) already in the post OOA southern Asian phase.

pconroy said...
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pconroy said...

I would say that those who can't tan and have dark hair - like me - are older than those who can't tan and have blonde hair?

pconroy said...

Onur,

BTW, there was a Turkish gyro/falaffel place in Queens, New York that I used go to, and one guy there has blonde/brownish curly hair, blue eyes and freckles, and I was 100% certain that he was Irish, till he spoke and revealed himself to be Turkish.

I'm from Ireland myself, and this has never happened before to me.

onur said...

I cannot say I am impressed by your story, Conroy. If that guy was an ethnic Kyrgyz or Pakistani, for instance, I could be impressed.

Maju said...

Yah, it did not impress me the least either. Whoever who has visited Turkey knows that there is great variation and that the majority of the people resemble more Europeans, even non-Mediterranean Europeans quite often, than Indians or Egyptians. There are a lot of blonds, just like in any Northern Mediterranean country.

PConroy's surprise can only spring from ignorance. If all you actually know of Turkey is the comic of the Simpsons I read yesterday, that depicts ALL Turks as brown skinned with turbans, then...

And I would not say that untannable black haired is older than tannable black haired. Being able to tan and untan has many obvious adaptative advantages while hair color is trivial (neutral). Additionally yellow hair seems to be quite old in Eurasia - otherwise it is hard to explain its important presence among Australomelanesians.

pconroy said...

Maju,

What are you smoking - you both misunderstood and misquoted me in one post??

First, of course I've seen Blonde Turks before, but what I was talking about was a combination that looked distinctly Irish - that's very unusual.

Second, of course tannable dark haired is older than untannable dark haired - but what I mentioned was untannable blonde haired?! Obviously, untannable skin is pretty much only found in Northern Europe, or people of same descent, but it looks like Blonde hair is a more recent feature. It is of course NOT neutral, as it also lightens the skin a little, and the transition to cereal farming meant that people in Northen Europe needed to become light skinned fast to absorb enough vitamin D.

Yes, Yellowish haired Australian Aborigines and PNG people exist, but I never saw any data that the same genes were involved - so barring new information it's probably convergent evolution.

Maju said...

Sorry if I misunderstood you but, anyhow, I'm too used to see blonds with freckles or not, redhairs with freckles (mostly) and all sorts of people (in Italy, Spain, Basque Country and even Morocco) and while Turks do have a somehwat distinct variance from SW Europe, it's more of craniofacial traits maybe than a matter of skin/hair color, I think.

Yes, Yellowish haired Australian Aborigines and PNG people exist, but I never saw any data that the same genes were involved - so barring new information it's probably convergent evolution.

My opinion is exactly the opposite. I think that the genes involved were lurking among early Eurasians and were consolidated or displaced locally largely due to founder effects.

Of course I'm also in wait of new discoveries in this aspect but the fact that it is an Eurasian-specific trait suggests to me that it appeared (or became sufficiently dominant as to manifest) within the early Eurasians. And I guess the gene(s) is surely lurking there in recessive form and small ammounts in those populations that are normally black haired.

You see the occasional blond or light brown haired SE Asian and children in India sometimes have that trait too. Myself (my mother's word - I can't remember) was born blond and became black haired soon after birth. And you go around here to any school or playground and you see many blond or light haired kids - but you see very few adults that way. It is in any case a trait that manifests more strongly among children.

onur said...

First, of course I've seen Blonde Turks before, but what I was talking about was a combination that looked distinctly Irish - that's very unusual.

That is why I used as examples Kyrgyz and Pakistanis. They can have light hair, freckles and light eyes too (though much less than Turks). But the distinctively Irish look is very unusual for them, and not so unusual for Turks.

Dariush said...

while Turks do have a somehwat distinct variance from SW Europe, it's more of craniofacial traits maybe than a matter of skin/hair color, I think

What distinction did you notice at Turks?

Maju said...

Comparing with Spainards, for example, they have often broader, more "square" faces. Types like Gul are uncommon here.

Turks (and Spaniards and many others) are variegated, so it's difficult to pinpoint any single trait. But looking at some pics right now, Turks may remind me of Germans, Jews or also other West Asian/Balcanic/Caucasian peoples often - depending on the individual. A very small minority retain some East Asian traits but that's not something really widespread enough to consider.

Just my impresion anyhow - because what is true for some cases is false for others.

Dariush said...

But looking at some pics right now, Turks may remind me of Germans, Jews or also other West Asian/Balcanic/Caucasian peoples often - depending on the individual. A very small minority retain some East Asian traits but that's not something really widespread enough to consider.All those populations you mention are mainly Alpine-Dinaric (including the Armenoid variety). They can also be found in Iran, though not as common as in Turks.

Sound of the Occident said...

@Dariush:

As a 100% Turk living in Germany, it's extremely clear who is German and who is Turkish.

Maju meant that some of blond/light haired Turks may remind him Germans, but apart from extreme cases, not, I believe.

Turks aren't Alpine or Dinaric but mostly Armenoid mixed with Mediterraneans, especially in the West and North although this old school funny school classification is already dead.

Sound of the Occident said...

First, of course I've seen Blonde Turks before, but what I was talking about was a combination that looked distinctly Irish - that's very unusual.
--

Don't worry, 99,9% of Turks don't have curly blond hair, blue eyes and freckled skin...

Light hair (IMO, from light brown to platinum, red included) is not common in Turkey, I guess, not higher than 10%.

Maju said...

Well, I don't think of Germans as blond by default but I do think of them as somewhat corpulent and broadfaced. Of course there is variety but when I see a "Nordic" German (i.e. blond and longfaced) I think more of Ducth or Danish than strictly German.

So my considerations are more about how broad is the face and things like that than about how blond is the hair. But the variety is too wide to be too precise.

Take my example of Gul, who I believe is president or minister right now. That guy looks 100% Central or even Eastern European. Or Ataturk: he has almost the same facial traits as Hitler (broader eyebrows though).

Or take this pic of the first women MPs of Turkey (1935). Don't some of them look totally Central European? A very clear example to me would be Elgün, 3rd of second row, or the 4th one in that same row - but there are others. Yet others show noses that look very much like archetypical Jewish, etc.

... although this old school funny school classification is already dead.

Pretty much, I'd say.

onur said...
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onur said...
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onur said...

Maju and SotO, do you have scientific/statistical evidence to back your claims, or are you fully dependent on your personal experiences/observations? If it is the latter, I think it is pointless to continue this debate.

onur said...

Btw, complexional differences aside, I don't think we are much different craniofacially from Germans and other Central and Eastern (including the Balkans) Europeans.

onur said...

Craniofacial traits (not his complexion, he was blond and had blue eyes) of Ataturk reminds me Antonio Banderas. And Abdullah Gul somewhat resembles George Clooney.

pconroy said...

The Turkish guy I was talking about looked like soccer player Wayne Rooney - a very Irish look.

Maju said...

Onur: absolutely personal subjective impressions. I just tend to ignore pygmentation because I was raised in a very multicolor context (within West Eurasian variability), with syblings (and cousins) as dark as Sudanese Arabs or as light as Norwegians living side by side.

Btw, complexional differences aside, I don't think we are much different craniofacially from Germans and other Central and Eastern (including the Balkans) Europeans.

I think that's my point, even if haven't gone around with a ruler measuring people indeed. :)

And Abdullah Gul somewhat resembles George Clooney.

O_O

Not at all!

pconroy said...

I'd say Abdullah Gul look more like Rafik Hariri?

onur said...

And Abdullah Gul somewhat resembles George Clooney.

O_O

Not at all!


Actually, that was not my own claim (unlike my Ataturk claim). It was a claim that circulated for a time (somewhat jokingly) in the Turkish popular media. I myself have always likened Gul to a rich Arab sheikh.

Ponto said...

I thought we were discussing Basques and other Europeans not Turkish Turks from Anatolia. Yes I know part of Turkey is in Europe.

You folks must have a lot of queer blond haired people in your countries. Most blond haired people I know tan very well and very dark, darker than many darker haired people. I know that myself as I have dark hair and grew up with a lot of blonds. I was the only untanned one in summer, the one with skin peeling off my chest, face and back. Blond people tan very well, you should forget that idea that having blond hair means the skin does not tan. You are thinking of the people from the Celtic fringe of Britain, most of whom are dark haired but a lot are blond and red haired and they do not tan. I am of that stock. Swedes, Norwegians, Finns, Estonians and other mostly light haired Europeans are not of Celtic stock and tan like Black men, quite dark.

Now with regard to Basques. They are isolated from other Europeans genetically otherwise they would not have such high R1b, Rh- or high Blood group O. High Blood group O is very Mediterranean, Islander not mainland Mediterranean and very Irish, Scots and Welsh Celtic. If Basques can be distinguished as a group from other Europeans on genetic frequencies of proteins or types of genes tend they are isolated from other Europeans. Simple.

I am haplogroup J1, supposedly so Levantine, Arabian Peninsula yet there are Basques and Galicians and other near neighbours in Spain and nearby Portugal who are J1 and have African haplogroup E. It is likely that the distinctiveness of Basques is due to restrictive matings, inbreeding.

The study seems to be another attempt to show that Iberians are Europeans and not North Africans. That inferiority complex of Iberians is getting very annoying.

Maju said...

Now with regard to Basques. They are isolated from other Europeans genetically otherwise they would not have such high R1b, Rh- or high Blood group O.

Actually Basques are also high or intermediate in blood group A. What we have is virtually no group blood B, which is more common towards the East (and reaches highest densities in many parts of Asia).

Anyhow, all those traits are very typically European: R1b is found elsewhere and is likely original from West Asia but is most concentrated in Western Europe (and, within that region, among Basques, Gascons and Atlantic Celts). Much of the same can be said of blood peculairities like high Rh- and very low B: Rh- is almost a European-exclusive trait (is found at much lower levels in Africa and is almost zero in East Asia or among American or Australian Natives). All these three genetic traits are similar in their "Europeanness" or "Western Europeanness" and in all three cases the populations where they are most concentrated are exactly the same: Basque, Gascons, Bretons, Cornish, Welsh, Irish and Scotts.

But Basque-Gascons are not so closely related to Atlantic Celts (as is apparent for instance in mtDNA or autosomal genetics). So this cannot mean a common recent origin but rather the preservation of ancient common European/Western European traits that have become more diluted in neighbour populations, which have been more exposed to admixture.

I am haplogroup J1, supposedly so Levantine, Arabian Peninsula... Or North African possibly too. I am more and more persuaded that J1 is old in North Africa and J2b in Europe (and India).

...yet there are Basques and Galicians and other near neighbours in Spain and nearby Portugal who are J1 and have African haplogroup E.

And in Britain too. J1 and E appear to be very rare among Basques anyhow. Even J2, which is the most common clade after R1b and I, is very low. Iberians are another story.

The study seems to be another attempt to show that Iberians are Europeans and not North Africans. That inferiority complex of Iberians is getting very annoying.

This paper is not about "Iberians" but about Basques. And the only thing that seems to underline is that Basques are not "inbred" as you like to claim without any evidence and that we are not anything so special in the context of Western Europe.

It is likely that the distinctiveness of Basques is due to restrictive matings, inbreeding.

That is precisely what this study seems to disprove.

Anyhow, there is no distinctiveness in Basques, except for some locally peculiar lineages (rare ones anyhow) and for the fact that, when properly researched, we appear as a distinct cluster from both Iberians and Central/North Europeans. This is only logical if you study Paleolithic Europe: Iberia proper, the Franco-Cantabrian region and Central Europe were three interconnected but different provinces. At that time the Franco-Cantabrian region was surely themost important one demographically but this preeminence vanished later on, since Epipaleolithic times. This ancient distinctiveness of the FC region seems to have survived particularly among Basques and Gascons, who have been rather closed (but never totally) to foreign influences since then.

It is possible that peoples like Scots, Irish or Welsh represent also best the ancient Central-North European type, before Neolithic and post-Neolithic waves arrived to their original homeland in the Rhin-Danub area. But in these cases we should also consider the possibility of Epipaleolithic founder effects as well.

candida said...

Blond people tan very well, you should forget that idea that having blond hair means the skin does not tan.
_____

If you take a vacation in Spain, you quickly realize that the only people who burn in the sunshine are the British and Irish.

Germans (including me) and Scandinavians tan very well, they proudly show their brown skins in the summer.

Onur said...

I just re-read Maju's posts in this thread. Based on his definition, I am a standard white as opposed to Mediterranean (I have a skin tone which Maju would call standard white rather than café-au-lait and I easily tan under the sun). This is expected as I am a son of, by Maju's definition, a Mediterranean (café-au-lait skin tone) father and a Nordic (watered down milk skin tone, easily passes as a northern European) mother.

Maju said...

Onur: I did not say that the "standard white" skin tone is derived from admixture, I actually tend to imagine that it is the base European and Highland West Asia skin tone. Nordic quasi-albino (not tanning) variants (which are minority even in the far North) are peripheral exaggerations (whatever the exact genetic triggers, surely excess accumulation of blondism genes or peculiar locally important ones).

Whatever the case I do not see the Nordic variants as "pure" and the Mediterranean/Middle European ones as derived but the other way around.

While in some areas (Palestine, SW Balcans, West Iberia) North African genetic influence is somewhat apparent, elsewhere I don't think that there is any relevant secondary genetic influence from the South influencing skin tone.