Sunday, January 10, 2016

IBS for Tigrinyas and Xamir Agaws

Thanks to David Wesolowski we now have IBS data for Tigrinya and Xamtanga speaking people:


I thought something like this would be an interesting exercise and I suppose shows in ways beyond ADMIXTURE that Habeshas like the Tigrinya are closest to fellow Horn African populations who speak Afro-Asiatic (Cushitic & Ethiopian Semitic) languages. 

Using formal stats (f-stats, D-stats etc.) might've been rather uninformative in this regard in that all Horn Africans like Somalis due to their West Eurasian admixture would also share a lot of genetic drift with West Asians like Yemenite Jews or Yemenite Muslims who themselves even have African ancestry hence IBS seemed like a good way to display "closeness" in this case.

Although, the shared "mixed" nature of these particular Horn Africans probably had some part in amplifying why they seem so close in regards to IBS.

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  1. Why do these Xamir Agaws in certain PCA plots behave like they have more affinity with Somalis than the Beta Israel or Amharas?

    Also, their reduced Omotic levels relative to Beta Israel Agaws seems very odd.

    Something off about them. What explains this all?

    1. Do you mean in global PCAs? Well, that's simply because they're less West Eurasian than Habeshas like Amharas or Tigrinyas (I'd say they're about ~45-46% or so) but I'm not seeing what you're seeing:

      They generally plot closer to Beta Israels than to Somalis. As for their lower Omotic scores... I don't know, to be fully honest. A friend more familiar with the areas they live in once theorized that they generally remained more "isolated" because of the mountains and rivers or some such surrounding where they live. And I suppose they just incurred less of certain admixtures as a result? All I can muster at this juncture.

    2. I meant in regional intra-Horn of Africa plots. In some that I have seen they behave quite different from other Ethiopian highlanders in the Omotic to Somali axis.

      The Xamirs drift away from the Beta Israel and Amharas when there is an Omotic to Somali axis. This seems quite unusual as Xamir Agaws aren't really known for being related to Somalis.

      Perhaps they are Afar mixed.

    3. I've only ever seen a few PCAs where an "Omotic axis" or affinity is apparent:

      (shared along with some other similar PCAs in some length here:

      In both cases, I mostly don't see what you mean. In the first PCA or set of PCAs; they remain quite unflinchingly among other Northern Highlanders like Amharas and Tigrinyas. In fact, some of the Beta Israel look like they veer away towards Somalis more. Whilst in the second PCA, only ONE of the "Afar" (Xamir Agaw) samples breaks the clime toward Aris & Mota and looks to pull toward Somalis.

      I really don't see what you mean. Could you show me these PCAs you're thinking of?

    4. It depends. Sometimes it doesn't show, while in other PCAs I saw it shows. Like this old one from Dienekes:

      (He used more Somali samples than usual (own project and Pagani's).

      And this one as well:

      The Xamirs who originally were labled Afar shift noticeably towards Somalis relative to the other highlanders.

      It is also reflected by their lower than average Omotic autosomal % in some runs as well.

      Something's up.

    5. They're not that much less "Omotic" than Tigrinyas. In one one run where Tigrinyas are at 11% they're at 9% IIRC.Though they are much less "Omotic" than Amharas and Beta Israels. Those pulls you shared are interesting but I think they can easily be explained by two factors I've already touched upon in the past...

      These Agaws have less of the "New West Eurasian" elements in the Northern Highlands and a little less "Omotic" ancestry (particularly less than Amharas):

      They're as a result clearly "closer" to Somalis than Habeshas & Betae Israels are. I don't find a pull in them toward Somalis as particularly surprising as a result. But those two pulls you shared aren't entirely "massive" (the second one is pretty overt though). But who knows...

      Perhaps they are "Afar" admixed. The mislabeling of these samples has always weird-ed me out. I even recently contacted Luca Pagani and he thought there was a mix-up in the supplementary table and that they were indeed Afars but had to check with an associate of his who was in charge of all that; the associate seemingly hasn't gotten back to him. These samples are too close to Habeshas and Beta Israels and fit too well among them to be Afars plus the co-ordinates and sampling location shared for them was clearly not in the Afar region but the Amhara region in an area where the Xamir live but perhaps you're onto something and they have a little Afar admixture. I don't know... Something has to explain why someone would mix Xamirs up with Afars or vice-versa.

    6. It is a fascinating mystery! I'm open to the possibility of them just being regular 'ol Afars, but remain skeptical of it. For now, I will view them as Xamirs until strong evidence to the contrary comes up.

      Regarding Afars, I am not sure if they are similar to Somalis at all considering their nonexistent V32 & T and elevated J and other types of E1b1b's (V6? IIRC). They could just be a language shifted older group of Cushites who adopted a Lowland East Cushitic language recently while their old 'true' language which may have been Beja or Agaw related or what have you was lost.

      Southeast Oromos are without a shadow of a doubt related to Somalis (genealogically and linguistically), but the relationship between Somalis and Afars is a bit murky.

    7. I actually wanted to make a blog post about this but got held up. I was basically going to highlight how "distinct" they seem from Somalis in terms of Y-DNA:

      In my humble opinion, Afars will likely seem more similar to other "Ethiopians" than Somalis are and not turn out "identical" to but perhaps just somewhat shifted toward us. Afars do show T & V32 btw, it's just that they show pretty low levels of them. I highly doubt they're language shifters (although the assimilating of other groups shouldn't be ruled out) but they're probably "Omotic" admixed given how they carry Y-DNA E-M329 like Amharas do (a marker linked to "Omotics" IIRC) and may even have some of the later West Eurasian admixture in the Horn although I've been told that their J1 seems distinct from the J1 found in Habeshas and Agaws but I'm not sure about that. We'll see.

      I too am open to these Xamirs being real Afars but so far they just fit too well as Agaws so until evidence to the contrary is made apparent; I'm sticking to that characterization.

      Sahos may turn out less "divergent" from Somalis than Afars based on their Y-DNA (they look they've bottle-necked the hell out of E-V22... I've even heard of pre-Trombetta et al. Y-DNA results for about 12 Sahos and they too were E-V22) but who knows...