Liya Kebede, Credit
There is a new paper, Ethiopian Genetic Diversity Reveals Linguistic Stratification and Complex Influences on the Ethiopian Gene Pool, which is being sensationalized in the media. For example, the BBC headline: ‘DNA clues to Queen of Sheba tale’. I assumed that this was just the media, but to my surprise the authors themselves mention the ‘Sheba tale’ in their discussion for various reasons. This is unfortunate. Though it is true Ethiopians have a legend of descent from the queen of Sheba (and through her relationship to king Solomon the ancient Hebrews), if there is a scholarly consensus about the location of Sheba, it is probably in southwest Arabia (i.e., modern Yemen). But the reality is that it is probably just as likely that the story in the Hebrew Bible is an interleaved synthesis of legend and reality, and that disentangling the nuggets of truth so as to establish the location of the real Sheba is going to be impossible (it is just as likely that the real queen of Sheba, if she existed, was a Levantine notable who was given a more exotic provenance by the redactors of the Hebrew Bible).
As for the paper itself, it is of some interest. I’ve blogged and analyzed Ethiopian data myself, but the sample coverage here is awesome. Additionally, the authors attempted to ascertain time since admixture in relation to the Ethiopian population for their West Eurasia and African ancestral components, as well as sniffing around for signatures of selection in the genome. The highlights:
In the open thread someone asked: “Any recent stuff on the genetics of Ethiopians.” That prompted me to look around, because I’m curious too. Poking around Wikipedia I couldn’t find anything recent. A lot of the studies are older uniparental lineage based works (NRY and mtDNA). Ethiopia is interesting because unlike almost all other Sub-Saharan African nations it has a long written history. Culturally and linguistically it has both Sub-Saharan African, and non-Sub-Saharan African, affinities. The languages of highland Ethiopia are clearly Semitic. Those of lowland Ethiopia are Cushitic, a branch of the broader Afro-Asiatic language family concentrated around the Horn of Africa (Somali is a Cushitic language, though most Ethiopian nationals who speak a Cushitic dialect are of the Oromo group).
From a human evolutionary genetic perspective, Ethiopia also has specific interest. It is likely that the main recent pulse of humans Out of Africa traversed this region. Additionally, there is some evidence of deep time connections between the groups ancestral to Ethiopians and the Khoisan of southern Africa. It may be that Ethiopians and Khoisan are reservoirs of ancient genetic variation in Sub-Saharan Africa which as been overlain by Bantu in most other regions outside of West Africa. Finally, Ethiopians are known to have high altitude adaptations. This could be due to long term residence in the region, or, assimilation of favorable alleles from the long term residents by later populations.
Fortunately we can get a sense of the genetic affinities of Ethiopians thanks to a paper published last spring, The genome-wide structure of the Jewish people. The focus was clearly on Jews, but they surveyed Amhara & Tigray (Semitic speaking highlanders), Ethiopian Jews (similar ethnically to the Amhara & Tigray, but religiously non-Christian), and Oromo. In the PCA the Oromo and Semitic speaking populations are pretty obviously distinct clusters.