South African sheep breeds: Population genetic structure and conservation implications

This paper details the population genetic structure of South African indigenous, locally developed and introduced breeds using microsatellite markers, and the conservation implications of these results. Blood samples from 622 sheep, comprising 20 breeds, were collected from different regions in South Africa. All animals were genotyped at 12 microsatellite loci. Average unbiased heterozygosity (Hz) was lowest in the fat-rumped breeds (0.466); compared to higher average Hz values of 0.555 and 0.598 in the composite and indigenous fat-tailed breeds; and still higher values of 0.659 and 0.662 in Karakul and the wool breeds respectively. Analysis of patterns of differentiation showed that the average Fst value between fat-rumped and the fat-tailed indigenous breeds was 0.180, with an average Fst = 0.184 between indigenous fat-tailed and wool types, and a higher average Fst value of 0.260 between fat-rumped and wool type breeds. Fst values within breeds were generally lower. Results from both Bayesian analysis (STRUCTURE) and a neighbor-joining tree based on standard genetic distance confirmed the known patterns of relationships among these groups and (in some instances) breeds. The results of this study also suggest that the indigenous breeds studied have some uniqueness, which may well translate to local adaptation over time. These results thus provide additional support for programs aimed at the conservation of indigenous and locally developed breeds, in line with international programs that emphasize the conservation of indigenous animal genetic resources. (C) 2011 Elsevier B.V. All rights reserved.