Horn Africans: A mixture between East Africans & West Eurasians

I recently got my 23andme results and they bolstered me to perhaps try and speed up getting to work on a post like this. 

Somalis

I've touched on many subjects about Horner / Horn African (Somali, Ḥabesha, Agaw, Oromo, Ari etc.) ancestry and of course made clear mentions of the fact that most of the Cushitic, Semitic & even Omotic speaking peoples of the Horn of Africa are substantially West Eurasian admixed but I never actually made any clear cut lone post about this admixture like I recently did for Central Asians and I figured such a post was long overdue.

You see; as has been noted in several studies on our autosomal DNA (I'm a Somali); Horners like Somalis, Amharas, Oromos, Tigrinyas, Xamir Agaws and Beta Israels / Ethiopian Jews are quite West Eurasian admixed. [1] [2] [3]

Note that the "Afar" used in these studies are not actually Afars

 The above table is from Pickrell et al. 2013; an extensive peer-reviewed genetic study on the West Eurasian input in Eastern & Southern African populations and it displays what I'm talking about quite straightforwardly.

As does the PCA / cluster (Principal Component Analysis) above from Hodgson et al. 2014 utilizing autosomal DNA which allows you to assess and display a group's ancestry. As you can see; Somalis, Tigrinyas, Oromos, Wolaytas and so on all cluster as intermediates between mostly non-Eurasian admixed African groups like the Yoruba of Nigeria or Dinkas from South Sudan (other Sub-Saharan Africa samples to the far left) & West Eurasians like Arabians.

West Eurasia

Again; clearly displaying our basal intermediacy between the two groups owed to the fact that we're seemingly the result of ancient mixing (seemingly episodic in many senses) between West Eurasians and a currently "extinct" African population. 

I say "extinct" because the East African cluster that tends to make up lets say ~60% of the ancestry in your average Somali & ~50% of the ancestry in your average Ḥabesha no longer exists in what one could call "pure form"...

It peaks in Nilo-Saharan speaking peoples sure but in the end mostly all of them have Niger-Congo admixture which Horners completely lack for the most part so they're not representative of the non-Eurasian ancestry [-] in groups like Somalis & Amharas.

What you see in this "Nilo-Saharan" component that forms much of our ancestry and theirs is seemingly just extremely ancient shared ancestry.

Honestly though I wouldn't make too much of modern ADMIXTURE components until we someday have adequate ancient DNA data from across Africa & Eurasia-> we'll understand the African and even West Eurasian ancestry in Horners much better and be conclusive about things once we have such data like we're getting nowadays with West Eurasia and some other regions.

Nevertheless, it is ultimately the case that on a basal level; we look to be a mixture between a mostly (I'd say ~98%) non-Eurasian admixed African component and West Eurasians.

Amharas

The West Eurasian ancestry itself is also pretty interesting in that Horners (whether its Somalis, Aris or Amharas) all seem to be for the time being entirely "ENF" / "West Asian" admixed. Completely lacking Ancient North Eurasian / MA-1 related ancestry as well as Western European Hunter-Gatherer or WHG-like ancestry outside of what could be making up ENF with Basal Eurasian. 

As you can see; Horner groups like Amharas, Somalis, Ethiopian Jews and so on all come out entirely "ENF" admixed which attests very much to the ancient nature of most if not all of the West Eurasian ancestry in these groups.

The results from David Wesolowski's K8 model above are also supported by the results of Lazaridis et al. 2013's K=20 ADMIXTURE analysis [4]:

Link to the ADMIXTURE run

Horners like Somalis & Amharas lack Ancient North Eurasian and Western European Hunter-Gatherer/ "Unknown West Eurasian Hunter-Gatherer" (WHG like ancestry) input in that analysis above as well; this time from a peer reviewed genetic study from some esteemed geneticists from Harvard Med and other institutions of great repute.

If you're wondering about "Early Neolithic Farmer" though; we don't know too much about it... For now it just seems like what you would get if you account for what shows up as Western European Gatherer ancestry in Early European Farmers like Stuttgart. It tends to peak in the following populations in the K8 model:


It carries Basal Eurasian possibly alongside something similar to WHG in my humble opinion. We will in truth need ancient genomes from West Asia and perhaps even East Africa to truly grasp this component and the Basal Eurasian component it carries.

For now, any inferences about it other than it does carry Basal Eurasian are just speculation and all you should keep in mind is that it's ultimately a West Eurasian ancestral component and the results above displayed in those two Eurogenes K=8 based charts go in line with what is already outlined in various peer-reviewed genetic studies; that Horn Africans like the ones in the first chart carry a lot of West Eurasian ancestry. 

I wouldn't rack my brain over too much else like extreme details on these components themselves until we have ancient genomes to contend with. Things most likely will prove a lot more complex with these components / clusters once we have ancient genomes from West Asia and neighboring regions like North and East Africa to compare modern groups to.

On another note; this autosomal DNA data on Horners which is ultimately what's most important when assessing a population's ancestry is backed up by the Haplogroups of these same Horner ethnic groups:


As the video I linked to above with the word "Haplogroups" will tell you; Haplogroups are mostly a mark of migrations and such. A person can easily be 99% Chinese autosomally/ in terms of their actual ancestry but turn up with a typical Somali Y-DNA marker like E-V32 simply because they coincidentally have a single male Somali ancestor from about ten generations ago for example.

But ultimately the Haplogroup data in Horners is often quite in line with what you get from their autosomal DNA data (ADMIXTURE results and PCAs etc.) and that's that they're an intermingling between "East African" (a bit of a misnomer as a great many modern East Africans from Sudan to Tanzania are non-negligibly West Eurasian in ancestry) & West Eurasian ancestries.

(For further info on the Haplogroups of various Horners as well as a higher resolution look at the mtDNA data above go to Ethio-Helix's blog: [-] [-] , it's all sourced with peer-reviewed studies on population genetics)

Now, if you're a complete layman when it comes to Population genetics; you're probably wondering what each of these lineages signifies. Well, for starters the J-M267 / J1 in Amharas & Afars is basically a Eurasian marker, West Eurasian to be exact:

It also has an obvious spread among African groups with non-neligible West Eurasian ancestry

Whilst A-M118 is an "African" marker that tends to peak in populations with essentially no West Eurasian input like South Sudanese groups. The same situation can be found with Amahar & Tigrinya mtDNA markers (or Somali mtDNA markers). N & M are overtly Eurasian while L0 & L5 and such are overtly African.

Tigray-Tigrinyas

 One thing though that someone reading this should keep in mind is that not all Horn Africans / Horners are like the groups I'm touching on in this post. There are plenty of populations in the Horn who are quite genetically distinct from what you find amongst Somalis, Oromos, Ḥabeshas, Aris & Wolaytas. Such as the Anuak & Gumuz in Ethiopia or Rashaidas and Kunamas in Eritrea or Arabian & Bantu populations in Somalia.

Note


Anuaks as you can see are mostly "African" and mostly lack any Eurasian (West Eurasian) input whilst your average Rashaida probably wouldn't differ much from the numerous Saudi & Bedouin samples you see out there given that they're the descendants of recent migrants who showed up in Eritrea around 200 years ago.

The so far tested Omotic speaking group (Aris) whilst carrying non-negligibly West Eurasian ancestry are also arguably still pretty distinct from Somalis & Ḥabeshas and for example are notably less West Eurasian than those two groups, so don't fall into the trap of thinking every last group in the Horn is like the groups I'm touching upon; the majority seemingly are though.

Horn of Africa

 Finally, one more point I would like to place absolute importance in understanding is that West Eurasian ancestry in Horners is simply not owed to recent input. By recent I mean where many ethnic Somalis think we're somehow a mixture between Arabians & "native peoples", a mixture that may have occurred around ~1400 years ago or so.

Or where some Ethiopians I've encountered ignorantly think they're the result of the same kind of mixing that occurred between South Arabians & "native peoples" 2-3 thousand years ago. These myths are owed to a plethora of misunderstandings such as the Somali peoples' fabled but fraudulent Arabian genealogies & perhaps also the fact that groups like Amharas speak South Semitic languages. 

I want you to tenaciously observe the ADMIXTURE analysis above from Hodgson et al. 2014. Now, Hodgson et al. had a lot of flaws in some of its assertions but its results are often quite useful (it did also make good points I touch upon about the unreliable dating in studies like Pagani et al. which I note in that old post of mine about the study).

For one; it discovered an ancestral cluster it dubs "Ethio-Somali" that forms at the higher Ks amongst Somalis, Oromos, Wolaytas, Ari Cultivators, Tigrinyas & Amharas:

Now, what this ultimately shows as I tend to explain in this detailed post about the more recent shared ancestry between these groups is that it refutes the idea that any of these groups actually got most of their West Eurasian ancestry from the events their members misguidedly tend to think they did. [note]

To put it simply. That component also shows up in both Somalis & Ḥabeshas like Amharas & Tigrinyas who haven't shared a gene pool arguably in about +3,000 years  and not just that but the component also shows up in the Maasai who are South Cushitic admixed.

West Eurasian ancestry extremely similar for the most part to the ancestry you'd find in Somalis for example also shows up in various Khoi-Kwadi speaking groups who are, like the Maasai; South Cushitic admixed:

"Putative Eastern African ancestry" = basically South Cushitic admixture

This ultimately speaks strongly to the ancient nature of this West Eurasian ancestry.

And not just that but components like "Ethio-Somali" & the "Lowland East Cushitic" component from Shriner et al. 2014[5]- :

Cyan colored component peaking in Somalis

-ultimately tend form in genetically isolated and often somewhat inbred ethnic groups who haven't endured outside admixture in a long while. For Somalis it's quite evident that all of the West Eurasian ancestry in us is basically extremely ancient (pretty much entirely within these components) and most likely goes back far enough to a time when the ancestors of Somalis & the ancestors of lets say Beta Israels / Ethiopian Jews or South Cushites shared a gene pool or at the very least clearly and grossly predates the medieval Islamization of Somalis.

 
(the model above is explained here)


In conjunction with this autosomal DNA data; the Haplogroups you find in modern day substantially West Eurasian admixed Horners as a friend once noted- :

"Y-DNA J1 is more diverse in Ethiopia than Arabia, indicating an ancient presence in the former and some sort of bottleneck in the latter. There is even J*, so neither J1 nor J2, in the Maale Omotics from southwestern Ethiopia. Many Eurasian mtDNA lineages in the Horn like M1, U6, R0a, N1a etc. are often substantially differentiated from lineages found in Arabia. M1 is even almost nonexistent in Yemenis from various parts of the country according to Cerny et al., and autosomally, modern Arabians are significantly more affiliated with more northerly West Asian populations than the Middle Eastern component found in the Horn and the Maghreb" 

-are not really compatible with a massive recent influence from places like the Arabian Peninsula.

Truthfully; we will need ancient genomes from across East Africa, North Africa and West Asia to truly grasp the history of both the East African cluster based and West Eurasian ancestry in modern Horn Africans but for now it's quite clear much of this admixture is quite ancient.

I would place the earliest influence in some of these groups at circa. 800 to 1000 BCE when the Central Cushitic speaking ancestors of modern Ḥabeshas linguistically shifted to South Semitic [7], this could explain the extra amount of "New West Asian" ancestry Ḥabeshas have over Agaws like the Xamir and recently Ethio-Semitized Agaws like Ethiopian Jews but that's mostly speculation on my part.

Oromos

I suppose I'll see someday if I'm still alive when they start sampling ancient remains across the Horn and various other parts of Africa and West Asia  but for the time being; that along with a lot of what I outline in many of my older posts about the Horn is what we tend to know about Horner ancestry.

In the end though Horn Africans / Horners like the groups I've touched upon and ones seemingly closely related to them (Afars, Sidamas, Gurage, Sahos etc.) are all ultimately on a fundamental level a mixture between West Eurasian & non-Eurasian / African ancestry that tends to peak in groups like the Dinka.

I strongly advise reading all of the posts I'm going to be recommending below and also the peer-reviewed papers I tend to cite.

Reference List:

1. Ancient west Eurasian ancestry in southern and eastern Africa, Pickrell et al.

2. Ethiopian Genetic Diversity Reveals Linguistic Stratification and Complex Influences on the Ethiopian Gene Pool, Pagani et al.

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

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

5. Genome-wide genotype and sequence-based reconstruction of the 140,000 year history of modern human ancestry, Shriner et al.

6. Bayesian phylogenetic analysis of Semitic languages identifies an Early Bronze Age origin of Semitic in the Near East, Kitchen et al.

Recommended reads:

1. Sudanese Arabs, Beni-Amer Beja and Nubians: Autosomal DNA data

2. The Oromo people: Heterogeneous

3. The Jewishness of Ethiopian Jews

4. The Omotic Cluster: A Horn Specific Cluster

Notes:

1. I would note that much of the West Eurasian ancestry in Horners while ultimately West Eurasian is probably African mediated / owed for example to populations that were probably by majority West Eurasian in ancestry but geographically resided in Africa itself; North Africa in particular. They may have had East African cluster like ancestry themselves but honestly; we'll know when we have sufficient ancient genomes from across Africa and Eurasia.

2. If you're anyone from an as of yet generally un-sampled (in terms of autosomal DNA) Horner ethnic group (Afar, Saho, Sidama, Gedeo, Kambaata, Gurage, Benadiri, non-Ari or Wolayta Omotic speaker, Somali Bantu etc.); do order a 23andme kit and if you wish: email me your raw data as well as your Haplogroup data once you have your results.

It would really be extremely enlightening to see some hint of your group's genomic data via you and perhaps some of your acquaintances and relatives. It won't be like a peer-reviewed population genetics study or anything extensive (small number of samples to work with) but it'd be extremely intriguing nevertheless. My email: Awaleking@gmail.com

3. I advise you to keep reading this blog (looking at newer posts) because newer and newer studies keep coming out and I might have to tack extra details onto what's in this blog post (i.e. some of the new stuff we know about some of West Eurasian that might be in some Horn Africans).

Revisiting Dobon et al. 2015: The Fulani Samples

I thought it would be interesting to note that the Sahel wondering Fulanis Dobon et al. 2015 sampled were seemingly two or perhaps several distinct subgroups of Fulanis. 

Northeast Africans + Maasais + Southern Levantines +  Arabians PCA

One group for one seems almost homogeneously less West Eurasian than usual for Fulanis in my experience. They essentially seem about as West Eurasian as your average Gumuz whilst the other looks clearly more West Eurasian and pulls left across the X axis toward Southern Levantines, Nagada Copts and Arabians and seem perhaps more representative of other Fulanis like those in Hodgson et al. 2014. [3]

The Sahel

Could this heterogeneity be owed to the fact that when you look at the info shared on the Fulanis; their location is simply listed as "Sahel" (and not a single location/ town/ these were probably wondering pastoral nomads; they in fact are just listed as "nomads" for their "location")? The people in charge of gathering the study's samples probably sampled various distinct Fulanis as a result in my humble opinion but one interesting thing to note is that both the more West Eurasian Fulanis and the less West Eurasian ones demonstrate a clear affinity for Northwest Africans:

Link to the PCA

Virtually all of the Fulani samples began pulling south on the Y axis the same Moroccans, Tunisians & Mozabites do. This is relevant because both they and Moroccan Jews (who also pull south in that PCA above) are known to have non-negligible Northwest African/ Maghrebi admixture. [2] [3]

You see, Fulanis don't get their West Eurasian ancestry from actual West Eurasians like Europeans or West Asians but via proxy from Northwest Africans who themselves are ~70-80% West Eurasian:

This influence from Northwest Africans to Fulanis has been known for a while now and can be demonstrated via ADMIXTURE analyses from studies like Hodgson et al. 2014:

Notice the light green "Maghrebi component" and its substantial presence in Fulanis... It's also interesting to note that David/ the author of the Eurogenes genome blog ran some of these Fulani samples from Dobon et al. through Eurogenes K=8 and they like Northwest Africans/ Maghrebis seemed to have demonstrated Western European Hunter-Gatherer ancestry.

He mentioned that one group essentially lacked such ancestry but another was about 5-6% WHG (these are probably the more West Eurasian Fulanis who pull more to the left on the PCAs I shared and that are ultimately owed to him). [note about the WHG in Northwest Africans]

So it's interesting to note that even those highly African Fulanis are basically still to some small extent Northwest African admixed though they must be barely Northwest African admixed as they cluster more or less as far left as the Gumuz and the Gumuz are very lightly West Eurasian admixed thanks to their seemingly very ancient Omotic admixture:

[4]

If they're comparable to that extremely low level of West Eurasian ancestry; I personally wouldn't put their general Northwest African ancestry over ~5% or so but it's clear that it is present given how they demonstrate at least a tiny amount of West Eurasian ancestry and display an affinity for Northwest Africans in a PCA.The other more West Eurasian Fulanis are clearly substantially Northwest African admixed though.

Reference List:

1. The genetics of East African populations: a Nilo-Saharan component in the African genetic landscape, Dobon et al.

2. The genome-wide structure of the Jewish people, Behar et al.

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

4. Ancient west Eurasian ancestry in southern and eastern Africa, Pickrell et al.

Notes:

1. Lazaridis et al. 2013 ADMIXTURE run & Harappa world ADMIXTURE run (an example of a run with "Mediterranean" in it)

2. The Gumuz as one compatriot of mine once pointed out likely have a very ancient strain of Omotic admixture, perhaps from a  time when Omotics were far less West Eurasian/ West Asian admixed as they actually have a very substantial amount of "Omotic" ancestry in mostly all runs where Omotic/ Ethiopic shows up but are clearly not very West Eurasian (their est Eurasian ancestry is almost negligible). 

We'll see someday with further study done on various Ethiopian & East African populations & perhaps someday if and when we have ancient genomes from across East Africa.

3. The "Sub-Saharan African" ancestry Northwest Africans display in Eurogenes K=8 is a mix of the East African cluster/ component with some Niger-Congo speaking peoples based African ancestry like what peaks in Yorubas in the higher Ks of many runs like what I mentioned in my blog post about Dobon et al.'s Copts.

4. The "Afar" samples in that last table from Pickrell et al. (reference 4) aren't actually Afars.

Central Asians: A mixture between West Eurasians & East Asians

From looking at them alone many maybe curious about the genetic nature of groups like Kazakhs, Uyghurs, Uzbeks, Hazaras, Turkmen, Kyrgyz and so on. They can display extremely East Asian-esque features but in conjunction with this often display more typically West Eurasian phenotypic traits such as blue eyes or light brown to blonde hair.

Kazakhs

The reason behind this is that at a basal level (ancient / pre-historic ancestry); they're a genetic mixture between West Eurasians and East Asians. The product of such intermixing that's been going on since the Bronze Age based on data from the recent Allentoft et al. 2015. [1]

Now, of course, Central Asians are no monolith. Many Tajiks, Uzbeks and Turkmen can honestly be by majority West Eurasian and perhaps only about ~20% East Asian (if not less).

Kazakhs who are in my experience far less heterogeneous can seem more like an even split between East Asians & West Eurasians but mostly all Central Asians do have some non-negligible East Asian ancestry and then also some non-negligible West Eurasian ancestry & are, for the most part, a cross between East Asians & West Eurasians.

You can see what I'm talking about above where Kazakhs, Turkmen, Uyghurs show a gross amount of West Eurasian (Early Neolithic Farmer, Western European Hunter-Gatherer & Ancient North Eurasian) ancestry in conjunction with East Eurasian (basically East Asian) ancestry. [note on South Eurasian]

And below you can see the heterogeneity I mentioned among groups like Uzbeks, Tajiks and Turkmen:

So I'd remain cautious with looking at the averages for various Central Asian populations run through the Eurogenes K8 Model (some info on the author of Eurogenes / David Wesolowski) based charts above and assuming virtually every member of each ethnic group would turn out like that.

Central Asia

This isn't just true for Central Asians though but for non-West Asian Turkic speakers at large (Kazakhs, Uzbeks, Turkmen, Kyrgyz & Uyghurs are all Turkic peoples). Altaians, Bashkirs & Yakuts who can be found in areas like Siberia or generally "Northern Eurasia/ Russia" (whilst being Turkic speakers) are also more or less "West Eurasian + East Asian":



This mixed nature is ultimately why Central Asians, various Siberians and such can display the kinds of sometimes unique looks that they do. 

This mixed nature is not just demonstrable via simple ADMIXTURE analyses and ancient DNA like with the recent Allentoft et al. but can be perceived often via PCAs (Principal Component Analysis)  as well where groups like Uyghurs & Yakuts often cluster as intermediates between West Eurasians and East Asians who more or less lack West Eurasian input (like the Japanese):

Central Asians like Kazakhs, Kyrgyz and so on, regardless of how they look, are not 100% East Eurasian by any means but are instead a cross been East Eurasians (East Asians in this case) and West Eurasians. Granted, many Central Asians and non-West Asian Turkic peoples can be more one than the other; with this sort of heterogeneity sometimes existing profusely in a single ethnic group like with Uzbeks.

I'm really no expert on Central Asia, Turkic speakers or really even Siberians but I was pseudo provoked into making a post like this upon encountering some people online who were bickering quite a bit over whether or not groups like Kazakhs were "purely" East Asian and well... This is the answer.

Reference List:

1. Population genomics of Bronze Age Eurasia, Allentoft et al. 2015

2. Reconstructing Indian population history, Reich et al.

Notes:

1. All of these groups do also carry Basal Eurasian ancestry as "ENF" (what Early European Farmer would be if you removed its WHG) basically caries Basal Eurasian.

Recommended read:

The complex admixture history and recent southern origins of Siberian populations, Pugach et al. 2015

The Savanna Pastoral Neolithic: A Cushitic Culture that genetically influenced various Southern Africans

Not too long ago I'd read an intriguing paper by Roger Blench about ancient pastoralist Cushitic speaking peoples who culturally influenced the Khoikhoi groups of Southern Africa and noticed how this correlated with the genetic data on some of these populations they were known to have culturally influenced in that these groups demonstrated what looked to be Cushitic admixture. [1] [2]

This lot Roger Blench touched upon are generally known as "The Savanna Pastoral Neolithic Culture", a culture at the earliest dating back to ~3200 BCE in the Kenyan lowlands, with a later presence in the Tanzanian highlands by ~1200 BCE and an even later presence in parts of Southern Africa as early as ~200 BCE. [3] [1]

They were Cushitic (South Cushitic) speaking cattle pastoralists (whilst also possessing goats and sheep) and tended to bury their dead in cairns whilst their toolkit was characterized by stone bowls, pestles, grindstones and earthenware pots. Some even suggest that they practiced irrigation and cultivated grains such as millet though there's still some arguing to be done about that. [3] [5] 

They ultimately ended up spreading pastoralism across Southeastern and Southern Africa prior to the Bantu expansion. 

Southern Africa

But what this post is ultimately about is not explaining this culture to you (reading Blench's paper, their Wikipedia page and several other books or papers on them can do that for you just fine) but touching upon the genetic impact they seemingly left on the group's they culturally influenced in Southern Africa.

Afar nomadic tent

.

Nama nomadic tent

What you see above is one example of a cultural influence the peoples of the Savanna Pastoral Neolithic culture left in Southern Africa... They passed on what Roger Blench identifies as a signature form of tent making among Cushitic speaking peoples in Northeast Africa to Khoikhoi / Khoe-Kwadi speaking peoples like the Nama. 

Bejas, Afars, Somalis, Rendilles and so on all practice or historically practiced this method of raising tents that Blench refers to as "mat-houses" or some refer to as "mat-tents". 

A painting of Khoikhoi pastoralists dismantling their tent

They also notably passed pastoralism onto some of these Hunter-Gatherer groups in Southern Africa prior to the arrival of Bantu-speakers after the Bantu expansion. 

Modern spread of the Bantu (a subset of Niger-Congo) languages in Africa

It's quite interesting in that this means that Cushites were in Southern Africa before Bantu speaking peoples made their way there and were the first peoples to spread the fruits of the Neolithic Revolution across the region until Bantu agriculturalists and pastoralists arrived & absorbed both them and various "Khoisan" groups.

Now, whilst I can go on and on about the cultural influences these peoples left on groups like the Nama; you can read about that in Blench's paper or from other sources. What I'm delving into here is what looks to be actual genetic evidence for this contact that seems quite undeniable in an archaeological sense.

 Virtually all of these groups got their West Eurasian ancestry not from actual West Eurasians (though the Nama are more complicated and do have some European admixture) but from West Eurasian admixed East African pastoralists similar for example to your average Somali. 

I made a point of contacting the geneticist in charge of the study responsible for the above table via email:

I asked him quite directly if this West Euraisan ancestry in his opinion was owed to West Eurasians or to Cushitic speakers/ peoples genetically similar to ethnic Somalis and even shared Roger Blench's old paper with him to show him what I was talking about. 

I did so because many of the peoples his study had sampled (Khoe-Kwadi speaking groups like the Nama) were coincidentally the very peoples Roger Blench and others have touched upon and pegged for having a Cushitic-Afro-Asiatic cultural influence about them.

He seemed to agree with this as you can see above and believes they got their West Eurasian ancestry from East African pastoralists who themselves were West Eurasian admixed (basically like the Northeast African Cushitic speakers his study also tested) and to me; this + the known and solid Cushitic cultural influence in these groups definitely confirms this to be Cushitic admixture. 

The study he acted as a main author for ultimately demonstrates this:

 The Nama were excluded from this table because their European admixture complicates things but above you can see these groups basically modeled as "Khoisan + Cushitic + Bantu". With the Eastern African ancestry carrying West Eurasian admixture with it being their Cushitic admixture as in this table it's ultimately similar to the ancestry in the study's West Eurasian admixed Eastern African populations (Somalis, Oromos et al.):

In the end; it's quite interesting to know that South Cushites didn't just leave a genetic and cultural impact on Southeast Africa as I touched upon in the past but also made it as far as Southern Africa where it seems that they both culturally and genetically influenced various peoples across the region.

Reference List:

1. Was there an interchange between Cushitic pastoralists and Khoisan speakers in the prehistory of Southern Africa and how can this be detected? , Roger Blench

2. Ancient west Eurasian ancestry in southern and eastern Africa, Pickrell et al.

3. From Hunters to Farmers: The Causes and Consequences of Food Production in Africa, by John Desmond Clark, Steven A. Brandt

4. The Prehistory of East Africa, by Sonia Cole

Notes:

1. The "Afar" samples in that table above from Pickrell et al. aren't actually Afars.