The History of African Gene Flow into Southern Europeans, Levantines, and Jews

[Loki]

The History of African Gene Flow into Southern Europeans, Levantines, and Jews (http://www.plosgenetics.org/article/fetchArticle.action?utm_medium=feed&utm_campaign=Feed%3A+plosgenetics%2FNewArticles+%2 8Ambra+-+Genetics+New+Articles%29&utm_source=feedburner&articleURI=info%3Adoi%2F10.1371%2Fjournal.pgen.100 1373)

Abstract

Previous genetic studies have suggested a history of sub-Saharan African gene flow into some West Eurasian populations after the initial dispersal out of Africa that occurred at least 45,000 years ago. However, there has been no accurate characterization of the proportion of mixture, or of its date. We analyze genome-wide polymorphism data from about 40 West Eurasian groups to show that almost all Southern Europeans have inherited 1%–3% African ancestry with an average mixture date of around 55 generations ago, consistent with North African gene flow at the end of the Roman Empire and subsequent Arab migrations. Levantine groups harbor 4%–15% African ancestry with an average mixture date of about 32 generations ago, consistent with close political, economic, and cultural links with Egypt in the late middle ages. We also detect 3%–5% sub-Saharan African ancestry in all eight of the diverse Jewish populations that we analyzed. For the Jewish admixture, we obtain an average estimated date of about 72 generations. This may reflect descent of these groups from a common ancestral population that already had some African ancestry prior to the Jewish Diasporas.

Summary

Southern Europeans and Middle Eastern populations are known to have inherited a small percentage of their genetic material from recent sub-Saharan African migrations, but there has been no estimate of the exact proportion of this gene flow, or of its date. Here, we apply genomic methods to show that the proportion of African ancestry in many Southern European groups is 1%–3%, in Middle Eastern groups is 4%–15%, and in Jewish groups is 3%–5%. To estimate the dates when the mixture occurred, we develop a novel method that estimates the size of chromosomal segments of distinct ancestry in individuals of mixed ancestry. We verify using computer simulations that the method produces useful estimates of population mixture dates up to 300 generations in the past. By applying the method to West Eurasians, we show that the dates in Southern Europeans are consistent with events during the Roman Empire and subsequent Arab migrations. The dates in the Jewish groups are older, consistent with events in classical or biblical times that may have occurred in the shared history of Jewish populations.

http://www.plosgenetics.org/article/fetchObject.action?uri=info%3Adoi%2F10.1371%2Fjour nal.pgen.1001373.t002&representation=PNG_M

[Grumpy Cat]

Very interesting but... I predict you're going to end up locking this thread. :D

[Peasant]

http://imgur.com/Ojllm.jpg

[Libertas]

All this may or may not be true but it is no reason to keep accepting increasing African or Asiatic influxes into any part of Europe.

[Lábaru]

all Southern Europeans have inherited 1%–3% African ancestry

Not bad considering the thousands of years of border, we, the Spanish North, did a perfect job., in a few of years the whole of Europe will be twenty times more African genes, and not exactly from bereberes :mad:

[Raikaswinþs]

one drop rules uh? lol looks like you´re in the mood for some bashing. I portrait you now yielding your sword and screaming "Bring them om , those greasy dagos, all at once !!! wrrouaarrg!!"" btw loki, everybody knows Bilbao, and not Londinium , is the centre of the universe. This map will explain it to ya


http://bp1.blogger.com/_tpWAmfPJ3WE/Rx5Hj5z2XcI/AAAAAAAABII/3vZmaNE6_nQ/S570/mapamundi+de+bilbao.jpg

[Loki]

Polako blogged on it here:

Evidence of "recent" Sub-Saharan African admixture in Southern Europeans (http://eurogenes.blogspot.com/2011/04/evidence-of-recent-sub-saharan-african.html)

http://img852.imageshack.us/img852/602/gradient.jpg

Geographic gradient of African ancestry in Europeans. Sub-Saharan African ancestry proportions were estimated using f4 Ancestry Estimation. Populations in grey are estimated to have sub-Saharan African ancestry between 1–4%. The * in Switzerland indicates that the three populations available from this country have variable estimates: Swiss-Germans show no evidence of African mixture, Swiss-French 0.5±0.2% and Swiss-Italians 1.6±0.2%. The ‘+’ sign in Italy indicates that multiple samples were available but all show evidence of African mixture. No data are available from countries filled with diagonal lines.

[Foxy]

I am sorry Loki, you can't post a text where you say that ALL the Southern Europeans have more than 1% of African genes and then a scheme that says that in Sardinians and Northern Italians African genes are 0,2% and in Southern Italy and Spain a mere 1%. The only one that seems to have a relevant African admixture (more than 1%) is Portugal and Greece is not considered. Where is Greece?
An other thing that leaves me perplexed is the fact that these genes should be arrived in Southern Europe during the Roman Empire while Romans hadn't black slaves. Look better the Roman Empire extension:

http://www.fmboschetto.it/religione/Apocalisse/Impero_Romano.gif

Africa, for Romans, was modern Lybia and when they referred to "African slaves" they meant Berbers.
The only black slaves could be arrived from Southern Egypt but surely 99,9% of Romans slaves were from Europe, Northern Africa and Middle East and where sold in every part of the Empire including central Europe. So if the "responsible" of the arrival is really the Roman Empire,genetical borders cannot be so marked. Or the cause in an other one.

[Loki]

I am sorry Loki, you can't post a text where you say that ALL the Southern Europeans have more than 1% of African genes and then a scheme that says that in Sardinians and Northern Italians African genes are 0,2% and in Southern Italy and Spain a mere 1%. The only one that seems to have a relevant African admixture (more than 1%) is Portugal and Greece is not considered. Where is Greece?
An other thing that leaves me perplexed is the fact that these genes should be arrived in Southern Europe during the Roman Empire while Romans hadn't black slaves. Look better the Roman Empire extension:


It's not me who did the study. :) And they didn't say "all", they said "almost all".

In any case, this is just for scientific interest. Those levels are negligible and unimportant.

[Agrippa]

Dienekes, quite eloquently and with excellent arguments, just ripped this study apart:

http://dienekes.blogspot.com/2011/04/sub-saharan-admixture-in-west-eurasian.html

This is truly a new age for this field of science, because for the first time, if you know your stuff, are intelligent enough, capable technically and invest sufficient time, you can refute in a very short period of time "studies" made by "scientists" - which were in the past very difficult to question by laymen.

I mean in physical anthropology for example, you could, with actual knowledge of a given people, refute a given theory someone came up with. Because it was verifiable with a limited amount of means. Same for many other sciences in question to a certain degree.

Now the new age of genetics just brought us the hot meal, we could either eat it or leave it, but we couldn't do too much about it, because the means were only available to a chosen few.

But with programs and data being available to more people and the growing general understanding of the principles behind this studies and scientific research, the official scientists can no longer deliver crappy studies and getting away with it, unless another scientists with these means might write a critical article about it some months later.

And this excellent piece of Dienekes just proves that, actually he makes these "scientists" look like amateurs.

Really great stuff, Dienekes developed into something great with his blog! :thumbs up

Power to the people - in this field of science too - and no longer full dependence on crap produced by a few...

[Ibericus]

But this study is only K=3 (sub-saharan, Utah-whites and Chinese) which means the sub-saharan component includes other stuff, at least in Caucasians (mid-east, east-afr, north-afr, etc). In a K=11 like that of Dienekes the spaniards have only 0.1% sub-saharan, which is the same as that of British. Or the K=14 of Rhazib with 0% sub-saharan or the K=8 of Eurogenes with also 0%.

[Agrippa]

But this study is only K=3 (sub-saharan, Utah-whites and Chinese) which means the sub-saharan component includes other stuff, at least in Caucasians (mid-east, east-afr, north-afr, etc). In a K=11 like that of Dienekes the spaniards have only 0.1% sub-saharan, which is the same as that of British. Or the K=14 of Harappa project with 0% sub-saharan.

Obviously most of the "African admixture" in Europeans is Caucasoid from white Africa and semi-Caucasoid from East Africa, such numbers for RECENT WEST AFRICAN admixture are ridiculous.

[Rouxinol]

This is manipulation for their own interests. Thousands of scientific papers are biased by their authors' beliefs or intentions - this one would be no surprise. Now look at some of the members of the research team:

http://genepath.med.harvard.edu/~reich/Reich_People.htm

What would one expect from this? They're doing their job to undermine European preservation thought as saying "you have to accept massive immigration into your countries because you have this or that".

[Loki]

I am sorry Loki, you can't post a text where you say that ALL the Southern Europeans have more than 1% of African genes and then a scheme that says that in Sardinians and Northern Italians African genes are 0,2% and in Southern Italy and Spain a mere 1%. The only one that seems to have a relevant African admixture (more than 1%) is Portugal and Greece is not considered. Where is Greece?


Polako claims that ALL Italians have SSA admixture.

http://www.forumbiodiversity.com/showpost.php?p=360226&postcount=154




All Italians have some Sub-Saharan African admixture, including Swiss Italians. So if you're Sicilian, I wouldn't even have to scan more than a couple of chromosomes. It really wouldn't be any trouble.



It's not an insult or anything, just of historical interest. Nothing "wrong" about it. :)

[Grumpy Cat]

I'm pretty sure the SSA admixture is either noise, or perhaps a genetic similarity. There may be some admixture, but I doubt it's in ALL people.

A disease found in Southern Europeans and Levantines (not sure about Jews), thalassemia, is very similar to sickle cell, and maybe a similar gene is responsible, and shows up as an SSA marker on genetic tests.

But bringing up Levantines, I read that SSA gene flow comes from ports in the Levant being important in the Trans-Saharan slave trade. Again, though, I don't think would be in all people from that region. Frequency would probably be quite small.

[Agrippa]

I'm pretty sure the SSA admixture is either noise, or perhaps a genetic similarity. There may be some admixture, but I doubt it's in ALL people.

A disease found in Southern Europeans and Levantines (not sure about Jews), thalassemia, is very similar to sickle cell, and maybe a similar gene is responsible, and shows up as an SSA marker on genetic tests.

But bringing up Levantines, I read that SSA gene flow comes from ports in the Levant being important in the Trans-Saharan slave trade. Again, though, I don't think would be in all people from that region. Frequency would probably be quite small.

Also that's related to what I'm always saying, namely that genflow and genetic drift are two things, but selection is another.

It is quite obvious that certain blood traits were selected positive for example in Malaria regions, if that happened, you can no longer use it as a marker to estimate the original admixture, EVEN IF the trait was introduced by genflow from population X.

That is why f.e. Mongoliform traits can be also more common among certain populations than their Mongoloid percentage is and lower in others, depending on the selective pressures working for or against them.

If people ignore selection in these respects - same with bloodgroups - their conclusions must be faulty.

Yet it is perfectly possible and an objective scientific question to analyse how much of an admixture or tendency towards this or that population has.

But IN THIS CASE the methodology is the problem, not just some potential ideological influences which might be there or not - after all scientists too are just humans and they might make mistakes not willingly, but just because they had the wrong idea.

And it seems to me, that this is the case with this study and only the authority of it being produced by "official scientists" gives it some rest of credibility in the face of the facts.

[Raikaswinþs]

Well, we Iberians are a race of our own, only related to some peoples of southern france and to other spaniards or mixed spaniards in diaspora. That is something we know and are familiar with. "Spain is different" (that applies to our Iberian brothers the portuguese too) We don´t even look truly similar to other meds in the way germanic peoples or some slavic peoples do to each othe (I mean, as a whole, of course there are cases in which a Spaniard has Italian looks and vice'versa) . And I don´t think that an 1% of possible SSA admixcture is the answer to that clear difference. We have more than 1% of norther european admixture and yet we don´t look like germans. Even the blond and red haired spaniards are distinctively Iberian in appearance. There´s more Iberian blood and lineages in North Africa than viceversa

[Arch Hades]

The study said the Greeks didn't have any admixture and they were outliers on the PCA, or that they threw a wrench in the whole thing and thus discarded them i guess.


"We curated these data using Principal Components Analysis (PCA) [16] (Table S2), with the most important steps being: (i)Removal of 140 individuals as outliers who did not cluster with the bulk of samples of the same group, (ii) Removal of all 8 Greek samples as they separated into sub-clusters in PCA so that it was not clear which of these clusters was most representative, (iii)."


Another thing of note is it is Interesting that the STRUCTURE results came up with some pretty significant differences between their 'new methods'. In the study, the STRUCTURE results had the Sardinians and Northern Italians only 0.2% admixed while using their 'other method' they came out 2.9% admixed...so it's probably best to go with STRUCTURE results for all groups IMO. This type of discrepancy wasn't in other samples like the Palestinians, who are known to have Negroid/Sub Saharan admixture.

But another flaw of this study is the sample sets, they got it from the PORPES database and much of the database got their samples from diaspora populations and almost half of the samples did not have the origin of any grandparents observed.

http://i1227.photobucket.com/albums/ee431/Cuban-Basque/Novembreetal2008Table-S1.jpg

So anyway, not very conclusive IMO.

[Prince Carlo]

I am sorry Loki, you can't post a text where you say that ALL the Southern Europeans have more than 1% of African genes and then a scheme that says that in Sardinians and Northern Italians African genes are 0,2% and in Southern Italy and Spain a mere 1%. The only one that seems to have a relevant African admixture (more than 1%) is Portugal and Greece is not considered. Where is Greece?

No way non Sicilian S.Italians have 1% of african admixture. On Dodecad/Eurogenes we have around 0.5%(most of which is semi-caucasoid East African).

[Contra Mundum]

About the same percentage as Neanderthal ancestry.

[Andarijo]

Welcome to the Whiggerdom