History and genetic diversity of African sheep: Contrastingphenotypic and genomic diversity

Abstract

Domesticated sheep have adapted to contrasting and extreme environmentsand continue to play important roles in local community-based economiesthroughout Africa. Here we review the Neolithic migrations of thin-tailed sheepand the later introductions of fat-tailed sheep into eastern Africa. According tocontemporary pictorial evidence, the latter occurred in Egypt not before thePtolemaic period (305–25 BCE). We further describe the more recent historyof sheep in Egypt, the Maghreb, west and central Africa, central- east Africa,and southern Africa. We also present a comprehensive molecular survey basedon the analysis of 50 K SNP genotypes for 59 African breeds contributed byseveral laboratories. We propose that gene flow and import of fat-tailed sheephave partially overwritten the diversity profile created by the initial migration.We found a genetic contrast between sheep north and south of the Sahara anda west–east contrast of thin- and fat-tailed sheep. There is no close relationshipbetween African and central and east Asian fat-tailed breeds, whereas weobserve within Africa only a modest effect of tail types on breed relationships