History of African gene flow into Southern Europe, Jews, and Levantines

Angela

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See:
https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1001373

It's the big guns: Reich, Patterson etc. I don't know why they worked with Moorjani, who vastly inflated it the first time around.

"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.Author 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.""


My initial reaction is big whoops, but whatever.

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I never put my faith 100% on their dating of admixture. It's so often wrong. Given the difference between the scores of Southern Italy (still very small) and northern Italy, which indicates to me it probably diffused northward, and the fact it's in Spain, I would bank on the Muslim conquests as the time period. There weren't very many SSA people in the Empire, and we know that the Muslim forces contained people with SSA ancestry (we have the ancient DNA to prove it), and that they also imported slaves to work the lands they conquered.

Interesting it's so small, actually.

People shouldn't be surprised how much there is in certain parts of the Levant. Besides dribbles for thousands of years, perhaps, there is slavery to consider and movement of Yemeni tribes into the Levant. You can see it in the Palestinians and the Bedouin. It's double the amount in the Druze. I have to look it over carefully. I wonder if figures exist for the Lebanese and Syrians and if they are closer to the Druze, and how much the Saudis have. I would imagine the latter have more. Between this ancestry and all the Iranian, no wonder the closest people to the Anatolian Neolithic are Southern Europeans.

I don't at all understand why they wouldn't give us the Greek figures. They had to divide the Italians up into three clusters. Why couldn't they have done the same for the Greeks? The split was probably Aegean Greeks, Peloponnese, and Thessaloniki.

 
I was too hasty. The Spanish and Portuguese numbers make some sense; it’s the time of the Muslim invasions. The. Northern Italian number is either a typo or totally stupid and calls their method into question.


Let’s take 150 x the standard 30 years per generation. That’s 2500 BC.

What am I missing or doin wrong?
 
Hi Angela. A related study to the one you cited above by Botique et al 2013 "Gene flow from North Africa contributes to differential human genetic diversity in southern Europe" which was published 2 years after the 2011 paper in post #1. That paper notes the admixture is possibly related to North African sources and/Roman slavery, and of course slavery events over the last 1,400 years with Muslims, etc. Botique in their study hypothesize that some of the "African" admixture in earlier studies which document 1-3% SSA admixture might actually be North African. So the models used in earlier studies when they use Yoruba or San to capture SSA West or East African ancestry could be proxying or capturing ancestry that is actually North African, which is not included in those original studies, would be a correlated omitted. Botique et al 2013 thus include North African populations in their models and variable could have been from a North African source, with some populations there having some SSA admixture. From the paper,

"Contrary to past observations, Sub-Saharan ancestry is detected at <1% in Europe, with the exception of the Canary Islands. In summary, when North African populations are included as a source, allele frequency-based clustering indicates better assignment to North African than to Sub-Saharan ancestry, and estimates of African ancestry in European populations increase relative to previous studies." Figure 2 in the paper has a nice color graph and it breaks down SSA, North African and Near East Ancestry into Europe, etc.


https://www.pnas.org/content/110/29/11791

Anyway, hope this paper adds to the discussion.

Happy New years, PT
 
See:
https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1001373

It's the big guns: Reich, Patterson etc. I don't know why they worked with Moorjani, who vastly inflated it the first time around......

I never put my faith 100% on their dating of admixture. It's so often wrong. Given the difference between the scores of Southern Italy (still very small) and northern Italy, which indicates to me it probably diffused northward, and the fact it's in Spain, I would bank on the Muslim conquests as the time period. There weren't very many SSA people in the Empire, and we know that the Muslim forces contained people with SSA ancestry (we have the ancient DNA to prove it), and that they also imported slaves to work the lands they conquered. .......
..........
I don't at all understand why they wouldn't give us the Greek figures. They had to divide the Italians up into three clusters. Why couldn't they have done the same for the Greeks? The split was probably Aegean Greeks, Peloponnese, and Thessaloniki.



I get quite a lot of disapproval when I point out to read genetic studies with cautions, and with a critical mind.
Unfortunately, not all scientists are strictly objective, bias free and neutral as necessary. For example, Arnaiz-Villenaet al. published several academic papers making the claim of SSA origin for Greeks.

http://TISA99P105 (makedonika.org)

http://www.makedonika.org/processpaid.aspcontentid=ti.2001.pdf

This crappy study was totally refuted.

Five studies from Arnaiz-Villena claim that Greeks are genetically related more to Sub-Saharan (Ethiopian and western African) people than Mediterranean.:LOL::LOL::LOL: Is there robust evidence for this theory?

We have examined the scientific evidence and the answer is: definitely not. This misconception is due to Arnaiz-Villena's faulty methodology. Highlights from Arnaiz-Villena's various studies include:


http://greek-dna-sub-saharan-myth.org/

When people for the sake of accuracy try to set the record straight by refuting crappy studies, such as the Arnais-Villa paper, which falsely claims Greek relatedness to Sub-Saharan Africans, the critics are accused of racism or being anti- black, by default. So, there're folks who tell Europeans to embrace or celebrate SSA admixture in them even when it’s fiction or totally exaggerated, otherwise you’re a racist or bad person. Others use deflecting arguments by asking questions, such as these: Why do you care about skin color? Oh, you hate blacks? Are you're a far-right extremist? Caring about historical or scientific accuracy, wanting ancient populations to be correctly represented, even when it doesn't fit the PC narrative, is considered racist. Even on this forum you see folks engaging in unhealthy debating styles.


There's this thinking that misleading or manipulated genetic studies are good since they're done with good intentions, with the goal to counter racism, nationalism and Eurocentrism. Yes, genes, DNA don’t lie, but the involved scientists can still make them say what they want them to say, by using flawed or faulty methods.



 
Mea Culpa for bringing up the original study. What can I say? It was recently posted on Razib Khan's site, and I'd had a few glasses of wine, which I rarely do. :)

I didn't check the date. Funnily enough, I mentioned in the opening post that I wondered why they partnered with Moorjani again after he so overestimated the SSA the first time. I think this may "be" the paper where he so overestimated it, the one which Dienekes tore to shreds on his blog as soon as it came out! :)

Ah well, so it goes.

Perhaps I'll remove it so people don't get confused.

It does still amaze me how they didn't realize something was really wrong when the got a 2500 BC date for the admixture in Northern Italians!
 
I get quite a lot of disapproval when I point out to read genetic studies with cautions, and with a critical mind.
Unfortunately, not all scientists are strictly objective, bias free and neutral as necessary. For example, Arnaiz-Villenaet al. published several academic papers making the claim of SSA origin for Greeks.

http://TISA99P105 (makedonika.org)

http://www.makedonika.org/processpaid.aspcontentid=ti.2001.pdf

This crappy study was totally refuted.



http://greek-dna-sub-saharan-myth.org/

When people for the sake of accuracy try to set the record straight by refuting crappy studies, such as the Arnais-Villa paper, which falsely claims Greek relatedness to Sub-Saharan Africans, the critics are accused of racism or being anti- black, by default. So, there're folks who tell Europeans to embrace or celebrate SSA admixture in them even when it’s fiction or totally exaggerated, otherwise you’re a racist or bad person. Others use deflecting arguments by asking questions, such as these: Why do you care about skin color? Oh, you hate blacks? Are you're a far-right extremist? Caring about historical or scientific accuracy, wanting ancient populations to be correctly represented, even when it doesn't fit the PC narrative, is considered racist. Even on this forum you see folks engaging in unhealthy debating styles.


There's this thinking that misleading or manipulated genetic studies are good since they're done with good intentions, with the goal to counter racism, nationalism and Eurocentrism. Yes, genes, DNA don’t lie, but the involved scientists can still make them say what they want them to say, by using flawed or faulty methods.


I totally agree.
 
When I was at 23andMe they said that most of Europe does not have sub Saharan ancestry (don't believe it), except countries that had empires across the globe: Portugal, Spain, France, Britain, and places under Muslim control during the Middle Ages i.e Sicily and Malta.

My attitude is Seek and you will find. I am sure most of Europe has sub Saharan and North African ancestry, they just haven't gone out of their way to find it like they do with Mediterranean Europe. It is just like the East Eurasian ancestry of Northern and Central Europeans, and it is not just the Saami or the Finns, it was a part of the ancestry of the North Eurasian hunter gatherers who mixed with Eastern Hunter Gatherers and eventually into the Yamaya herders. There are different attitudes to African ancestry than East Eurasian or Native American ancestry.

I won't avoid the issue, there was slavery all over Europe, some of it was sub Saharan, North African and Near Eastern. And in some countries slaves were freed by their owners and entered the local population. In Malta, most slaves came from North Africa, Anatolia and the Levant. Some were sub Saharan slaves. Personally I think admixture is less than 1% sub Saharan and the rest is North African. Either way, it is not important.
 

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