Y haplogroup E3b1 in Somali males

A new study quantifies the extent of Eurasian (15%) and Sub-Saharan African (5%) paternal admixture in Somalis, a population which appears to be predominantly East African paternally. The authors also explain why the Somalis have low Sub-Saharan African admixture:

The time of the eastbound Bantu expansion was estimated to be 3400±1100 years ago.24 Bantu populations have high frequencies of E3a haplogroups.4 We have observed only a few individuals with the E3a haplogroup in our Somali population, thus, supporting the view that the Bantu migration did not reach Somalia.42 It has been suggested that a barrier against gene flow exist in the region.43 The barrier seems to be the Cushitic languages and cultures to which Somalis belongs. The Cushitic languages belong to the Afro-Asiatic languages that are spoken in Northern and Eastern Africa. The Cushitic languages and cultures are mainly found in the Somalis and the Oromos, one of the two main groups inhabiting Ethiopia.44, 45, 46. The Somali and Oromo languages have a high degree of similarity and the two populations share many cultural characteristics. The Somali and Oromo people live in clans with special patterns of marriage and the Somali and Oromo people have complex, interwoven pedigrees.44, 45

European Journal of Human Genetics (advance online publication)

High frequencies of Y chromosome lineages characterized by E3b1, DYS19-11, DYS392-12 in Somali males

Juan J Sanchez et al.

We genotyped 45 biallelic markers and 11 STR systems on the Y chromosome in 201 male Somalis. In addition, 65 sub-Saharan Western Africans, 59 Turks and 64 Iraqis were typed for the biallelic Y chromosome markers. In Somalis, 14 Y chromosome haplogroups were identified including E3b1 (77.6%) and K2 (10.4%). The haplogroup E3b1 with the rare DYS19-11 allele (also called the E3b1 cluster γ) was found in 75.1% of male Somalis, and 70.6% of Somali Y chromosomes were E3b1, DYS19-11, DYS392-12, DYS437-14, DYS438-11 and DYS393-13. The haplotype diversity of eight Y-STRs ('minimal haplotype') was 0.9575 compared to an average of 0.9974 and 0.9996 in European and Asian populations. In sub-Saharan Western Africans, only four haplogroups were identified. The West African clade E3a was found in 89.2% of the samples and the haplogroup E3b1 was not observed. In Turks, 12 haplogroups were found including J2*(xJ2f2) (27.1%), R1b3*(xR1b3d, R1b3f) (20.3%), E3b3 and R1a1*(xR1a1b) (both 11.9%). In Iraqis, 12 haplogroups were identified including J2*(xJ2f2) (29.7%) and J*(xJ2) (26.6%). The data suggest that the male Somali population is a branch of the East African population - closely related to the Oromos in Ethiopia and North Kenya - with predominant E3b1 cluster γ lineages that were introduced into the Somali population 4000-5000 years ago, and that the Somali male population has approximately 15% Y chromosomes from Eurasia and approximately 5% from sub-Saharan Africa.

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