Genetic Improvement and Utilisation of Indigenous Tilapia in Southern Africa

Southern African populations of Oreochromis mossambicus have been classified as genetic resources in aquaculture and conservation. Twelve populations, collected for evaluation and strain development, were characterised using fluorescent microsatellite DNA analysis. Five, dinucleotide repeat, microsatellite loci conveyed significant genetic structure (FST = 0.27, R ST = 0.29, P and two introduced populations. Genetic diversity differed for farm populations (Ho = 0.26, α = 1.75), wild populations (Ho = 0.39, α = 5.3) and introduced populations (Ho = 0.39, α = 4.4). Individual populations indicated suitable levels of genetic diversity for use in selective strain improvement programmes. Phylogenetic trees contained population clusters related to but not exclusively linked with geographic distribution. Phylogeographic interpretations were made to identify populations of conservation value. The twelve captive populations represent genetically distinct units that require management to preserve genetic material for strain development and conservation of natural populations.