Wednesday, December 2, 2015

Comments on Mota PCAs from Eurogenes

Thought I'd make some quick comments on David's PCAs (principal component analyses) utilizing autosomal DNA and aimed at seeing where the ancient Southwestern Ethiopian individual Mota from Llorente et al. sits in regards to modern populations:

The most interesting of all the PCAs has to be this one, in my humble opinion. I say this because Mota clearly demonstrates a sort of affinity for the likes of Ari Blacksmiths and Cultivators and both him and them form a sort of curve with Oromos, Wolaytas, Agaws and Ḥabeshas whom are populations with over Omotic-related admixture.

Somalis are excluded from this curve and instead look more like a mixture between West Eurasians and South Sudanese-related populations (at least related to what ancestry in these groups isn't related to the ancestry that dominates West-Central African populations such as Yorubans). 

This somewhat supports data from an old admixture analysis by a fellow ethnic Somali which posits that ethnic Somalis largely lack Omotic-related admixture but instead may display (in some admixture analyses for example) an affinity for "Omotics" due to very ancient shared ancestry between them (perhaps related to Afro-Asiatic migrations or some such?).

Further study will be needed, of course but these results are fantastically intriguing.

This other PCA is intriguing I suppose in that Mota displays a sort of pull toward Out-of-Africa (OoA) populations, more so than the likes of Yorubas, Mbutis and so on despite in Llorente et al. being painted as highly non-OoA influenced (0%). A colleague I correspond with finds this intriguing as it could mean he carries a notable amount of pre-historic East African ancestry that may have a stronger affinity than usual for OoA  populations; could be...

This PCA seems perhaps somewhat uninteresting in comparison to the two prior ones however it is fascinating that Mota clusters in this PCA with Hadzas. A population that seems similar to him in that it looks to be a mixture (for now) between African Hunter-Gatherer-related ("Khoisan" & "Pygmy") & pre-historic East African / "South-Sudanese-esque" ancestry (when you exclude a population like Dinkas' West-Central African / "Niger-Congo" related input).

The thing is, Mota also shares the most drift with modern Southwestern Ethiopians like Ari Blacksmiths (with this population for the time being tending to be the modern peak of the "Omotic" component) & this is enthralling because Mota in David's admixture analyses like Eurogenes K=36 turns up as substantially "Omotic":

Central African: 14%
Omotic: 68%
Pymgy: 14%
West African: 3%

Hadzas have turn up as substantially Omotic-related in the past as well such as in this old analysis that proves quite good at spotting the Omotic-related input in various Horn African populations (I'd say that's its main use):

Bandar's run K=7

 But of course, this does not need to imply actual Southwestern Ethiopian or Omotic speaker related input into Hadzas (wildly unlikely) but it's riveting that a pre-historic sample like Mota much like Ari Blacksmiths and Cultivators displays an affinity for Hadzas as well. Perhaps this implies some shared  pre-historic ancestry between the likes of some Southeastern Africans & the likes of Mota.

That last bit might be the case given that both some of the African ancestry in Hadzas & some of the African ancestry in Mota has displayed a weird affinity for Basal Eurasian admixed pre-historic West Eurasian populations at different times via tree-mix:

Hadza-related migration edge toward Stuttgart:

Mota-related migration edge toward :

Given Mota's strange pull toward OoA populations (perhaps I am making too much of this?) despite being claimed to be vastly less OoA influenced than all modern African populations Hadzas and Motas could share in a pre-historic East African / South Sudanese-esque element that is perhaps shifted more than usual toward Out-of-Africa populations which tend to point their origins toward East Africa from a genetic and archaeological perspective.

This last bit is pretty incredibly speculative and I place no great weight behind what I've said but I suppose it is food for thought.

Another thing I would note before finishing however is that in the last PCA; both the Hadza and Mota display a clear pull away from other Africans towards the direction of Hunter-Gatherer groups such as the Ju-Hoan-North though they do not pull exactly toward them but in their general direction (right); perhaps corroborating that Mota carries ancestry at the very least related to these types of  divergent African populations.

Reference List:


No comments:

Post a Comment