African ancestry in West Asian & North African Arabs

I've gotten some questions about this at forums like Anthrogenica via private messages and I suppose it would be something some people would generally be curious about so this post will be dedicated to pointing out just how much "African" ancestry is roughly present in West Asian and North African "Arab" populations or whether or not they have any.

As you can see in the global PCA above utilizing autosomal DNA and basically 166,000 SNPs; West Asian and North African "Arab" populations such as Yemenite Muslims, Saudis, Palestinians, Moroccans, Egyptians and so on; all display a clear northward pull towards populations in Africa, away from from the orange cluster whom Southern Europeans such as Sardinians are within.

The reason for this pull these populations demonstrate is owed to what is noticeable above [note] based on the results from the old Eurogenes K=8 ADMIXTURE analysis or because of similar notable levels of "African" ancestry in these populations as noted by Hodgson et al. 2014:

Yemenite Muslims tend to be at levels comparable to those of North Africans such as Egyptians and Morrocans or even Mozabites (varying between ~15-25% on average from what I've noticed) most likely due to the Arab Slave Trade which resulted in them incurring later West-Central African-related input seemingly from peoples like Southeast African Bantu speakers which is noticeable in the K=14 admixture results from Lazaridis et al. 2013-2014 below:

Basically, various Muslim West Asian "Arab" populations, as opposed to some of their non-Muslim counterparts (Lebanese Christians, most so far tested Egyptian Copts, Yemenite Jews etc.), show signs of West-Central African-esque admixture probably acquired via the Arab Slave Trade. [note]

The more "ancient" looking East African cluster-related "African" ancestry (pink cluster that forms much of Dinkas' ancestry above) seems markedly older and is present in their non-Muslim minorities at notable levels (~5-15% in Yemenite Jews) who in the eyes of some academics seem like a bit of a throwback to some of these regions' pre-Islamic genetic profiles [3].

At the end of the day, these "African" contributions in Arabian and later Arabized populations of the Levant & North Africa are undeniable and can even have effects on formal stat based analyses like d-stats where they've actually caused some trouble for geneticists such as Iosif Lazaridis when trying to gauge just how Basal Eurasian some of these populations were:

These "African" contributions are also noticeable via uniparental data, most notably in regards to maternal markers / mtDNA like with the below Hadhramauti Yemenites who practically show as many Macro-Haplogroup L (discounting M or N ones) / mostly post Out-of-Africa migration "African" derived lineages as various Horn African populations:
Though they don't seem entirely representative of all the regions of Yemen as other studies with  Yemenite samples show lower but still substantial frequencies of non-M & N (which are more or less "Eurasian") Macro-Haplogroup L lineages among Yemenites:

In the end it seems quite clear that "African" ancestry similar and related to much of the ancestry in modern Yorubas or Dinkas or Anuaks and such is found all over the so called "Arab world" and is something that can be noticed via both autosomal DNA & Haplogroups whilst being backed up by various analyses from ADMIXTURE, PCAs to formal stats.

Reference List:

1. Early Back-to-Africa Migration into the Horn of Africa, Hodgson et al.

2. Ancient human genomes suggest three ancestral populations for present-day Europeans, Lazaridis et al.

3. Genetic evidence for an origin of the Armenians from Bronze Age mixing of multiple populations, Haber et al.

4. Ethiopian Mitochondrial DNA Heritage: Tracking Gene Flow Across and Around the Gate of Tears, Kivisild et al.

5. Mitochondrial DNA structure in the Arabian Peninsula, Abu-Amero et al.

6. Introducing the Algerian Mitochondrial DNA and Y-Chromosome Profiles into the North African Landscape, Bekada et al.

Notes:

1. Some degree of variation is to be expected. Do not expect all members of every population to conform to these estimates perfectly (it's often why I use ballpark type estimates like 15-25%) as some variation is to expected but relatively all the members of any of these given populations do have at least some or notable "African" ancestry, this has been analysed too thoroughly at this point not to be the case.

2. I've generally placed the term "Arab" in quotation marks like "African" because it too is a rather broad term spread out across a rather ridiculously wide region due to Arabization, Pan-Arabism and so on. Many peoples who consider themselves "Arab" or whom are considered as such don't in fact have much or sometimes any Peninsular Arabian ancestry. I.e. The average Moroccan is closer to a Mozabite Berber than to a Saudi Arabian and I'd wager most Moroccans trace the overwhelming majority of their ancestry to the original Berber speakers of their region who were Arabized (and it certainly does seem to be so based on ADMIXTURE runs like the ones I've shared so far) .