Assessment of genetic variation in Bapedi sheep using microsatellite markers

Abstract

This study was conducted to assess genetic variation in Bapedi sheep using 14 microsatellite markers. Blood samples were collected from 174 unrelated Bapedi sheep on six farms in various districts of Limpopo and from the Agricultural Research Council Animal Production Institute (ARC-API) in Gauteng. Genotypes from other South African indigenous sheep, namely Zulu (N = 14), Damara (N = 11), Dorper (N = 8), and Namaqua (N = 11), were included to represent reference populations. The effective number of alleles averaged 5.6 for across the Bapedi flocks and was 4.9 for the reference breeds. Among the Bapedi flocks, the observed heterozygosity (Ho) ranged from 0.56 ± 0.05 to 0.69 ± 0.03 and expected heterozygosity (He) values were between 0.75 ± 0.04 and 0.88 ± 0.01. Thus, there is considerable genetic diversity within the Bapedi sheep populations. However, the fixation index was high, indicating the possibility of inbreeding becoming a problem for these flocks. A neighbour-joining tree was constructed from the estimates of Nei’s genetic distances among flocks. The presence of Bapedi sheep flocks on all of the main branches of the tree along with one of the reference breeds suggests the present-day Bapedi is not an entirely distinct breed and that there are genetic differences between flocks of these South African indigenous sheep. Sustainable breeding and conservation programmes are needed to control inbreeding and to foreclose possible genetic dilution of Bapedi sheep.

Keywords: genetic diversity, germplasm conservation, inbreeding, indigenous sheep