Genetic diversity of domesticated stocks of striped catfish, Pangasianodon hypophthalmus (Sauvage 1878), in Thailand: Relevance to broodstock management regimes

Thai stocks of striped catfish, Pangasianodon hypophthalmus (Sauvage 1878), have a relatively long domestication history (> 20 generations) that began with fish of Chaophraya River origin. The genetic diversity of this species was studied in six hatchery populations with two different broodstock management regimes (without introduction of either wild or domesticated stocks vs. with occasional introduction of either original or non-original populations) and in three wild populations (from the Chaophraya River and its tributary and from the Mekong River). The results, based on five microsatellite loci, revealed high allele diversity of the hatchery populations (Ar = 6.53–8.06) with the introduction of non-original stock (from the Mekong population) relative to those with the introduction of original stock (from the Chaophraya population) or without introduction (Ar = 3.18–6.06). Notably, heterozygosity was high in the majority of populations (Ho = 0.633–0.763; He = 0.593–0.834). Genetic introgression from the Mekong population was observed in every population, as revealed by Bayesian population assignment. The wild populations showed unexpectedly low allele diversity (Ar = 4.89–5.98) and were not genetically differentiated from the hatchery populations (as revealed by AMOVA).