Ethnic Groups in Ethiopia - Genetic Studies

Genetic Studies

Autosomal DNA

Wilson et al. (2001), an autosomal DNA study based on cluster analysis that looked at a combined sample of Amhara and Oromo, found that they share 62% of their genome with Caucasians (Ashkenazi Jews, Norwegians and Armenians), 24% with other Sub-Saharan Africans (Bantus, Afro-Caribbeans), 8% with Austro-Melanesians (Papua New Guineans), and 6% with Far East Asians (Chinese).

Tishkoff et al. (2009) identified fourteen ancestral population clusters which correlate with self-described ethnicity and shared cultural and/or linguistic properties in Africa in what was the largest autosomal study of the continent to date. The Burji, Konso and Beta Israel were sampled from Ethiopia. The Afroasiatic speaking Ethiopians sampled were cumulatively (Fig.5B) found to belong to: 71% in the "Cushitic" cluster, 6% in the "Saharan/Dogon" cluster, 5% in the "Niger Kordofanian" cluster, 3% each in the "Nilo-Saharan" and "Chadic Saharan" cluster, while the balance (12%) of their assignment was distributed among the remnant (9) Associated Ancestral Clusters (AAC's) found in Sub-Saharan Africa. The "Cushitic" cluster was also deemed "closest to the non-African AACs, consistent with an East African migration of modern humans out of Africa or a back-migration of non-Africans into Saharan and Eastern Africa."

Paternal Lineages

A composite look at most YDNA studies done so far reveals that,out of a total of 459 males sampled from Ethiopia, approximately 58% of Y-chromosome haplotypes were found to belong to Haplogroup E, of which 71% (41% of total) were characterized by one of its further downstream sub lineage known as E1b1b, while the remainder were mostly characterized by Haplogroup E1b1(x E1b1b,E1b1a), and to a lesser extent Haplogroup E2. With respect to E1b1b, some studies have found that it exists at its highest level among the Oromo, where it represented 62.8% of the haplotypes, while it was found at 35.4% among the Amhara, other studies however have found an almost equal representation of Haplogroup E1b1b at approximately 57% in both the Oromo and the Amhara. The haplogroup (as its predecessor E1b1) is thought to have originated in Ethiopia or elsewhere in the Horn of Africa. About one half of E1b1b found in Ethiopia is further characterized by E1b1b1a (M78), which arose later in north-eastern Africa and then back-migrated to eastern Africa.

Haplogroup J has been found at a frequency of approximately 18% in Ethiopians, with a higher prevalence among the Amhara, where it has been found to exist at levels as high as 35%, of which about 94% (17% of total) is of the type J1, while 6% (1% of total) is of J2 type. On the other hand, 26% of the individuals sampled in the Arsi control portion of Moran et al. (2004) were found to belong to Haplogroup J.

Another fairly prevalent lineage in Ethiopia belongs to Haplogroup A, occurring at a frequency of about 17% within Ethiopia, it is almost all characterized by its downstream sub lineage of A3b2 (M13). Restricted to Africa, and mostly found along the Rift Valley from Ethiopia to Cape Town, Haplogroup A represents the deepest branch in the Human Y- Chromosome phylogeny.

Finally, Haplogroup T at approximately 4% and Haplogroup B at approximately 3%, make up the remainder of the Y-DNA Haplogroups found within Ethiopia.

Maternal Lineages

The maternal ancestry of Ethiopians is similarly diverse. About half (52.2%) of Ethiopians belongs to mtdna Haplogroups L0, L1, L2, L3, L4, L5, or L6. These haplogroups are generally confined to the African continent. They also originated either in Ethiopia or very near. The other portion of the population belong to Haplogroup N (31%) and Haplogroup M1 (17%). There is controversy surrounding their origins as either native or a possible ancient back migration into Ethiopia from Asia.

Passarino et al. (1998) suggested that:

Caucasoid gene flow into the Ethiopian gene pool occurred predominantly through males. Conversely, the Niger–Congo contribution to the Ethiopian population occurred mainly through females.

While there is debate among the scientific community of what exactly constitutes "Caucasoid gene flow", the same study further stated:

Indeed, Ethiopians do not seem to result only from a simple combination of proto-Niger–Congo and Middle Eastern genes. Their African component cannot be completely explained by that of present-day Niger–Congo speakers, and it is quite different from that of the Khoisan. Thus, a portion of the current Ethiopian gene pool may be the product of in situ differentiation from an ancestral gene pool."

Scott et al. (2005) similarly observed that the Ethiopian population is almost equally divided between individuals that carry Eurasian maternal lineages, and those that belong to African clades. They describe the presence of Eurasian clades in the country as sequences that "are thought to be found in high numbers in Ethiopia either as a result of substantial gene flow into Ethiopia from Eurasia (Chen et al., 2000; Richards et al., 2003), or as a result of having undergone several branching events in demic diffusion, acting as founder lineages for non-African populations". The researchers further found no association between regional origin of subjects or language family (Semitic/Cushitic) and their mitochondrial type:

The haplogroup distribution amongst all subjects (athletes and controls) from different geographical regions of Ethiopia is displayed in Table 3. As can be seen graphically in Fig. 3, the mtDNA haplogroup distribution of each region is similar, with all regions displaying similar proportions of African 'L' haplogroups (Addis Ababa: 59%, Arsi: 50%, Shewa: 44%, Other: 57%). No association was found between regional origin of subjects and their mitochondrial type (v2=8.5, 15 df, P=0.9). Similarly, the mtDNA haplogroup distribution of subjects (athletes and controls) speaking languages from each family is shown in Table 3. Again there was no association between language family and mitochondrial type (v2=5.4, 5 df, P=0.37). As can be seen in Fig. 4, the haplogroup distributions of each language family are again very similar.

In addition, Musilová et al. (2011) observed significant maternal ties between its Ethiopian and other Horn African samples with its Western Asian samples; particularly in terms of the HV1b mtDNA haplogroup. The authors noted:

"Detailed phylogeography of HV1 sequences shows that more recent demographic upheavals likely contributed to their spread from West Arabia to East Africa, a finding concordant with archaeological records suggesting intensive maritime trade in the Red Sea from the sixth millennium BC onwards."

According to Černý et al. (2008), many Ethiopians also share specific maternal lineages with areas in Yemen and other parts of Northeast Africa. The authors indicate that:

"The most frequent haplotype in west coastal Yemen is 16126–16362, which is found not only in the Ethiopian highlands but also in Somalia, lower Egypt and at especially high frequency in the Nubians. The Tihama share some West Eurasian haplotypes with Africans, eg J and K with Ethiopians, Somali and Egyptians."