June 21, 2016

Panorama of African admixture

I remember how in the early days of online discussions of anthropology a constant topic of contention was whether African variation was the result of admixture, some of it within Africa, some of it from Caucasoids, or whether it was the result of climatic adaptation manifested in gradual clines (as opposed to clusters corresponding to physical types).

Well, I won't dismiss the role of climate altogether, but it's hard to argue for it much anymore now that we know that the two big fish in the African ocean of human diversity were the spread of Niger-Congo languages (from the west), and of Caucasoids (from the east) over the last few thousands of years, with a healthy seasoning of minor admixtures before and after. Once again it seems that old-style anthropology was right and the more fashionable and trendy attempts to dismiss it as "typology", "imposition of European colonialism through science" and the like were wrong.



eLife 2016;5:e15266

Admixture into and within sub-Saharan Africa

George BJ Busby et al.

Similarity between two individuals in the combination of genetic markers along their chromosomes indicates shared ancestry and can be used to identify historical connections between different population groups due to admixture. We use a genome-wide, haplotype-based, analysis to characterise the structure of genetic diversity and gene-flow in a collection of 48 sub-Saharan African groups. We show that coastal populations experienced an influx of Eurasian haplotypes over the last 7000 years, and that Eastern and Southern Niger-Congo speaking groups share ancestry with Central West Africans as a result of recent population expansions. In fact, most sub-Saharan populations share ancestry with groups from outside of their current geographic region as a result of gene-flow within the last 4000 years. Our in-depth analysis provides insight into haplotype sharing across different ethno-linguistic groups and the recent movement of alleles into new environments, both of which are relevant to studies of genetic epidemiology.

Link

7 comments:

Stéphane Mazières said...

Typo in Ogobara's surname in the author list, what a shame.

Dr. Clyde Winters said...

This paper is nonsense. It is found on hypothesis which do not reflect the African reality. Firstly,there is no Afro-Asiatic language family and the Bantu speakers did not originate in West-Central Africa. In addition, there is no discussion of archaeological evidence in support of any of the authors propositions, statistics should not be enough to support the hypotheses discussed in this paper.

Reading this paper is like reading any other racist Eurocentric article written at the turn of the 20th Century perpetuating the Hamitic myth.THE Hamitic myth states that everything of value ever found in Africa was brought there by the Hamites, allegedly a branch of the Caucasian race. Seligman formulated this hypothesis which led researchers to declare that the Fulani and Afro-Asiatic speakers were Hamites. This racist theory was abandon, but appears to be coming back into vogue among geneticists who lack knowledge about African history.

As a result, when this study declares that the Fulani, who are not of Eurasian origin, and the Afro-Asiatic speakers have a high frequency of Eurasian (white) admixture, this paper is just reinforcing a hypothesis that lacks credibility. The results of this paper only perpetuates the Hamitic myth, many researchers had thought was abandoned--but has remained constant by geneticist who dress the hypothesis up in new clothes based on statistics, instead of actual archeaogenetics evidence.

The authors assume that the Bantu migrated out of Cameroon 2,5kya. This is ludicrous because the Bantu had been living in the Nile Valley long before 500BC.

In summary this paper is maintaining the status quo dogma that the Bantu and the rest of the Niger-Congo speakers are true Negroes, and the Afro-Asiatic speakers and Fulani are Hamites, i.e., dark skinned Caucasians. This paper offers nothing new in relation to African genetics, it is a throwback back to the 1930's racist antropological studies.

ThatGuy CalledPhil said...

I read the rest of the report and to be quite honest it's description of admixture events doesn't seem that debatable.

They pretty much occurred in place where you expect, the Sahel and th Eastern Areas, regions of Africa that are pretty hard to argue for variation resulting from purely "environmental adaptation" when we have tribes that are blatantly shown with mixed/complex ancestry such as Fulani and Swahili. Though in respects to my general knowledge of Bantus, I find it easier to point out obvious events of Bushmen and Bantu mixing rather than Eurasian and Bantu ones.


Environmental adaptation through clines, based on what I've observed through reading old book of Africans from the 1800s, doesn't seem outside their speculation but then again it seems it was more viewed clusters, as was typical of work of that time.

For example, though I'm not 100% of Baker's influences in regards to 19th Century work, I'm fairly confident that many in the past came upon something close to A Paleo-negrid, Sudanid, Nilotid stance like Baker. However members that would generally fit these desriptions were more often dubbed "Mohammadean, Negro, and Nile River Negro".

However just as well you had those who somewhat over stepped there boundaries with how much of a presence of eursian ancestry were I certain tribes, as mentioned in Razib Khan's results of comparing Tutsis and Hutus.

Onur said...

Since this paper stirs things up for Afrocentrist propagandists such as Clyde Winters, we can say that it is on the right track. It basically proves that Sub-Saharan African genetic variation is largely the result of admixture from Caucasoids. Well done authors, you have done a great job.

ThatGuy CalledPhil said...

To Winters,

You didn't really read this too well, did you. Nowhere did third paper state anything remotely close towards the "Hamitic Hypothesis". For that to be the case, it would have to discuss how the reported Eurasian Admixture (which in regards Sub-Saharans would be the Eurasian/Afro mix of Afro-Asiatic speakers, Some MINOR admixture with Black populations of the Sahel/Savannah, and Coastal groups of Bantu speakers) would have a relation towards the spread of meaningful culture throughout Africa.

However it said nothing of the sort. BTW, "Afro-asiatic don't exist"?

https://en.wikipedia.org/wiki/Afroasiatic_languages

Then exactly what is this? Also, you do know that Bantu people are a particular Language group of Sub Saharans that occupy Central/Southern Africa correct?

The group of Blacks that occupy the Nile Valley are NILOTICS. They are a different group.

Can you back up you're claims with science?

ThatGuy CalledPhil said...

To Onur, I don;t mean to come off as a "Winters" if you catch my drift, but where does it say that African variation is "largely" the result of Caucasian Admixture?

Well, I guess I'm being stupid and I'm just think of Niger-Kongo populations and i should consider Horners, NiloSaharans, and Bantu Population Southern and East of Africa than yes your statement is correct.

BUt just referring to Niger Congo peoople, really it's just restraint towards southern/eastern bantus and percentages in some sahelians tribes referred to as "minor admixture".

duge_buwembo said...

You are correct modern research is debunking this racist crap. I have been looking into population genetics and you will be surprised about the genome in the Horn. Horners are mixed due to an ancient prehistoric back migration event from the middle east. And thus as much as 40% of their genome is West Eurasian. But that large 60% non Eurasian component is of interest. I have found the following blog by a Somali guy who has studies from the best Universities in the world:

http://anthromadness.blogspot.co.uk/2015/07/horn-africans-mixture-between-east.html?m=1

That 60% non Eurasian component among Somalis, Beja,Habesha and Oromo is closely related to the modern Southern Sudanese like the Acholi, Dinka and Anuak. Thus Horners are related to other Africans, they are indigenous to Africa and they are not part of a separate Caucasian race. They have admixture. Nobody with admixture can be assigned the label of Caucasian, black Caucasian or Hamite. These terms are false, there are no such thing as Black Caucasians in Africa and this is true for the rest of the world even in India. This is based on research into the deeply pigmented skin of black Africans. It's been proven that the Australoids that at times share the black African phenotype share the same alleles with black Africans regardless of the fact that genetic drift means that they have no modern African haplogroups. Australoids like the Andamanese are Asian negroes that retained their phenotype in Africa before their ancestors migrated out. Black skin evolved once over millions of years in Africa amongst the pre-human hominids. It's a trait passed down from ancestors.

So even in India there are no black Caucasians because Black Indians get this phenotypical trait from Australoid admixture. Which is not suprising because the Andaman Islands are located near South India and Sri Lanka. Their language is similar to the languages spoken in South India and Sri Lanka and they are closely related to these Asian populations.

Those are the facts. The major flaw in this debate is that scientific racists focus on recent history thus 30,000bc. The oldest modern human remains are found all across Africa even in Morrocco and have been dated as being more than 100,000 years old. I have a book by a prominent English Anthropologist that did this study and employed some of the best forensic Scientists to reconstruct the faces of these remains. They are all "Negroid" proving that the typical Negro Phenotype prevalent among Bantus and Niger Congo speakers as well as Nilotics in Sudan predates all other phenotypes like the so called Caucasoid/Caucasian. By the Book by Dr Alice Robert's it's called Evolution the Human story.