Genetic diversity of Arapaima gigas (Schinz, 1822) (Osteoglossiformes: Arapaimidae) in the Araguaia-Tocantins basin estimated by ISSR marker

The genetic diversity of the specimens of four natural populations of Arapaima from Araguaia-Tocantins basin was assessed within and among these stocks, using five primers for ISSR. COI (cytochrome c oxidase subunit I ) partial sequences confirmed that the specimens belongs to Arapaima gigas . The ISSR provided 168 loci, of which 165 were polymorphic. However, the number of loci for each population and expected heterozygosity values were low. AMOVA showed 52.63% intra-population variation and 47.37% inter-population variation. The F ST was high among all populations (F ST ≥ 0.25), however, the cluster analysis (PCoA) and Bayesian inference showed three major groups: Araguaiana-MT + São Félix do Araguaia-MT, Novo Santo Antônio-MT and Itupiranga-PA. The genetic distance was not correlated with geographical distance. The ISSR marker revealed that the populations of the Araguaia-Tocantins are structured and have a low genetic diversity. These are the first data from a population analysis using molecular markers for A. gigas of Araguaia-Tocantins basins and may be used to define the best management strategies and conservation projects for this species.