Figure 1

Population genetic differentiation of Nile tilapia, Oreochromis niloticus , across its natural distribution. Geographic representation of the 10 sampled populations of Nile tilapia within the natural distribution range of the species (shaded area) and summary of the genetic differentiation observed according to the clustering obtained from AMOVA analysis (see Table 4); (A) at macro-geographic level across Africa and (B) zoom on micro-geographic and temporal variability within the Volta basin. Separation times between hydrographical basins are based on paleontological information (see References in the Discussion section). The genetic differentiations are the average pairwise population value observed within (dotted line) or between (solid line) basins or ichthyological provinces and regions; calculations are based on R_ST at Macro-geographic scale, while on F_ST.at micro-geographic and temporal scales, according to the test suggested by Hardy et al. [35] (see Table 3 & 5 respectively). The population symbols refer to the different morphological sub-species: O. n. niloticus (black dot), O. n. vulcani (black diamond), O. n. cancellatus (black square) and O. n. filoa (black star) - (see Table 1 for population codes).