Early Back-to-Africa Migration into the Horn of Africa

2014/06/12 by Jason A. Hodgson, Connie J. Mulligan, Ali Al‐Meeri +1 · 1 citation
Biochemistry, Genetics and Molecular Biology · Arts and Humanities · #Forensic and Genetic Research #Forensic Anthropology and Bioarchaeology Studies #Digestive system and related health #Somali #Genetic genealogy #Biology #Genetic admixture #Population #Evolutionary biology #Genetics #Ancestry-informative marker #Population genetics #Ethnic group #Demography #Allele frequency #Genotype #Gene #Anthropology

paper · pdf · doi:10.1371/journal.pgen.1004393

openalex publication_date 2014/06/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

Genetic studies have identified substantial non-African admixture in the Horn of Africa (HOA). In the most recent genomic studies, this non-African ancestry has been attributed to admixture with Middle Eastern populations during the last few thousand years. However, mitochondrial and Y chromosome data are suggestive of earlier episodes of admixture. To investigate this further, we generated new genome-wide SNP data for a Yemeni population sample and merged these new data with published genome-wide genetic data from the HOA and a broad selection of surrounding populations. We used multidimensional scaling and ADMIXTURE methods in an exploratory data analysis to develop hypotheses on admixture and population structure in HOA populations. These analyses suggested that there might be distinct, differentiated African and non-African ancestries in the HOA. After partitioning the SNP data into African and non-African origin chromosome segments, we found support for a distinct African (Ethiopic) ancestry and a distinct non-African (Ethio-Somali) ancestry in HOA populations. The African Ethiopic ancestry is tightly restricted to HOA populations and likely represents an autochthonous HOA population. The non-African ancestry in the HOA, which is primarily attributed to a novel Ethio-Somali inferred ancestry component, is significantly differentiated from all neighboring non-African ancestries in North Africa, the Levant, and Arabia. The Ethio-Somali ancestry is found in all admixed HOA ethnic groups, shows little inter-individual variance within these ethnic groups, is estimated to have diverged from all other non-African ancestries by at least 23 ka, and does not carry the unique Arabian lactase persistence allele that arose about 4 ka. Taking into account published mitochondrial, Y chromosome, paleoclimate, and archaeological data, we find that the time of the Ethio-Somali back-to-Africa migration is most likely pre-agricultural.

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• Ethiopians [wikipedia]