"African" as it applies to "Arab" (or even North "African") admixture must be properly "classified" before it can be "quantified."
-Are we looking to detect "African" admixture or specifically "Sub Saharan African" admixture?
-If we are looking at uni-parental markers at what date is it appropriate to deem the origin of a SNP "African"? If we ignore the dates, do we then look at a geographical point of origin of a particular SNP to classify it as "African" or something else?
-When going by Autosomal runs what is is more appropriate: One run may show a population of Arabs (Jordanians) to share about 9% of ancestral clusters with Sub Saharan Africans while another run will show that same populations to share about 25% of ancestral clusters with Sub Saharan Africans. [180% Increase]
I opened up a previous thread HERE about this same issue. In short a Yemeni Sample's "African" % in creases from 6% to 15% when when using the East African Maasai instead of West African Yoruba as the reference population[150% Increase] The study notes this:
I think we need to classify exactly what is "African" and use multiple lines of evidence before the question can be properly answered. With the tools that we have if it can be demonstrated that a Horn African in a structure run is 30-4x% "South West Asian".........then I personally feel confident that "African" Admixture amongst "Arabs" Is probably a uniform % no less that 15% and could reach upwards to as much as some Arabs being "Half African".These data suggest that the source population for the African ancestry of the Yemeni population is more similar to the contemporary Maasai population than either the Luhya or Yoruba.
I find it interesting that there are Arabs, particularly in Oman and Yemen that look East African yet there are no East Africans that look Arab....East Africa of course being one of the Major sources of South West Asian admixture.
---------- Post added 2011-02-21 at 17:01 ----------
Last edited by beyoku; 2011-02-21 at 23:08.
Doctoris Scientia (2011-03-10)
you can read about it here: http://www.biomedcentral.com/1471-2156/10/59
and this is an important argument to why the E-haplogroup is likely Euroasian in origin, and it also explains why A and B is present in east africa, and ultimately explains why sub-saharans are the most genetically diverse, because they are highly admixed.
"The population that left East Africa to colonize the world -- including other parts of Africa -- carried only CT and L3. We know this because if A, B and L0-L2 had already been present in that population, then those haplogroups would have colonized the world too. But they didn't. Therefore, modern Ethiopians(and other horners) have ancestry that the original East Africans (i.e. OOA migrants) didn't have, so they're not representative"
that means that the CDEF-M168 ancestors where already differentiated and a distinct population from the paleoafricans who where A,B and L0-L2, in other words there was sub-structure in africa before the OOA migration. and then the euroasians returned to africa and mixed with the paleoafricans creating todays sub-saharans whose paternal markers came from euroasia.
Were did you get your information from? Mathilda?
However, several discoveries made since the Hammer articles are thought to make an Asian origin less likely:
Underhill and Kivisild (2007) demonstrated that C and F have a common ancestor, meaning that DE has only one sibling which is non African.
DE* is found in both Asia and Africa, meaning that not only one, but several siblings of D are found in Africa.
Karafet et al. (2008), in which Hammer is a co-author, significantly rearranged time estimates leading to "new interpretations on the geographical origin of ancient sub-clades". Amongst other things this article proposed a much older age for haplogroup E than had been considered previously, giving it a similar age to Haplogroup D, and DE itself, meaning that there is no longer any strong reason to see it as an offshoot of DE which must have happened long after DE came into existence and had entered Asia.
"Peter Underhill states that there will always be uncertainty regarding the precise origins of DNA sequence variants such as YAP because of a lack of knowledge concerning prehistoric demographics and population movements. However Underhill contends that with all the available information, the African origin of the YAP+ polymorphism is more parsimonious and more plausible than the Asian origin hypothesis. Other authors who have published or co-published works in support of an African origin the YAP+ include Luigi Luca Cavalli-Sforza, Toomas Kivisild, Spencer Wells, Linda Stone and Paul F. Lurquin."
^ lol at me using Wikipedia, but it gets the job done.
DE* has been found in Africa (more than a dozen across Africa), more so than Asia (2 in Tibet).
---------- Post added 2011-03-10 at 17:53 ----------
Furthermore, phenotype has no bearing on a country's geopolitical affiliation. One only need to look at countries like Argentina (predominantly Euro-descended), Mexico (pred mestizo), and the Dominican Republic (pred mulatto), all identify as Latin American.
The northern Sudanese have more in common (culturally) with me and you than they do Ethios.
Last edited by Asce; 2011-03-10 at 20:10.
Johnny Blaze (2011-03-10)
With no East African cluster and a simple sub-Saharan cluster that peaks in West Africa, Egyptians are clearly less sub-Saharan than Moroccans. Maghrebis cluster closer to Horners than those Egyptian samples in global plots. However, Egyptians are still closer to Horners in terms of genome-wide similarity (IBS, ASD) than Maghrebis are. Probably due to the shared ancient ancestry that is evident in many uniparental markers.
Indeed, Yemenis are heterogeneous, and this seems to be the result of recent Bantu ancestry, mainly. The Saudis sampled so far are clearly more homogeneous. I share with one Saudi guy at 23andMe, and many Europeans are closer to me genetically than he is.I'm fairly certain Yemeni populations were found to be far more heterogeneous racially than Saudis (and other gulf Arabs).
According to Doug McDonald I've got a tiny african segment on my 13th chromosome, probably from some north african merchant a 1000 years ago...