African sheep, like other domestic sheep, are domesticated
from the Asiatic mouflon (Ovis orientalis). They entered the continent
through the North and the Horn of Africa regions following
maritime and terrestrial trading routes. Ethiopia is one of the main
entry points of various plant and animal domesticates into Africa.
It is characterised by diverse agro-ecologies, ancient human ethnic
diversity and the presence of indigenous sheep breeds/populations
of unprecedented morphological diversity (e.g. tail types). Here, we
investigate the genome diversity and population structure of 146
unrelated animals from 11 Ethiopian indigenous sheep populations.
DNA was extracted from ear tissue punches and genotyped with the
Illumina Ovine 50K SNP BeadChip assay. Sheep populations from
The Caribbean, Europe, Middle East and China as well as from
western, northern and southern Africa were included to clarify the
genetic history of origin, introduction and dispersal of the species
into Ethiopia. Principal component analysis (PCA), clearly separated
all Ethiopian sheep from the other populations. Population structure
and phylogenetic (neighbour-joining tree) analysis subdivided
the Ethiopian indigenous sheep into three genetic clusters corresponding
to their tail morphology (rump fat-tailed, short fat-tailed
and long fat/thin-tailed population). It supports a common genetic ancestry for populations of each tail type in the country. Genetic distances
among the Ethiopian populations were positively correlated
with geographic distances (Mantel test, P < 0.001, r = 0.465) and the
highest genetic diversity was recorded in the fat-tailed (short, rump
and/or long fat-tailed) close to the Bab-el-Mandeb strait. However,
despite their distinct morphology and separate geographic distribution,
little genetic differentiation between Ethiopian populations are
observed. This is most likely a consequence of their ancient and
modern intermixing following their introduction into the country