Population structure of indigenous southern African goats based on the Illumina Goat50K SNP panel

In this study, the genetic structure of indigenous Tswana and Swazi goats using the Illumina Goat50K SNP array was investigated. Two South African commercial goat breeds were included to investigate admixture with the indigenous populations in southern Africa. A total of 144 DNA samples including Boer goats (n = 24), Kalahari Red (n = 24), Swazi (n = 48), and Tswana goats (n = 48) were genotyped. Statistical analysis was performed using PLINK version 1.07. Genetic diversity, measured as expected heterozygosity, was estimated at 0.390, 0.398, 0.413, and 0.387 for Boer, Kalahari Red, Tswana, and Swazi goats, respectively. The individual inbreeding coefficient varied from 0.019 ± 0.05 to 0.011 ± 0.06 for the Tswana and Swazi goats, respectively. The Principal component analysis clustered the populations according to geographical origin and breed type. Linkage disequilibrium (LD) for shorter intervals (0-10 kb) ranged from 0.44 to 0.56 and commercial breeds had higher values. Effective population sizes decreased with generations and at the 13th generation ranged between 87 for Boer to 266 for Tswana goats. The Tswana population exhibited the highest level of genetic variation and effective population size, which holds potential for improved production in marginal regions. A national strategy is required to maintain genetic diversity in communal goat production systems through well-structured breeding and conservation programs.