Abstract :
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.
