Genetic diversity of Pangasius krempfi in the Mekong river

Abstract

Pangasius krempfi is a large-bodied catfish distributed exclusively in the Mekong River. This is a long distant migratory species that migrates upstream for spawning. In wild population, the number of P. krempfi has declined due to overexploitation, pollution, habitat distruction. This situation may lead to the decreased genetic diversity of this species, undermining its adaptability and survival in nature. This study aimed to quantify genetic diversity of P.krempfi in the Mekong River using ISSR markers. The fish were collected from two locations downstream of the Mekong River basins of Vietnam: Ben Tre and Soc Trang. Genetic analysis was conducted on 20 individuals per population using 6 ISSR primers generated total 32 alleles with the size ranging from 2200 – 500 bp. Intra-population genetic diversity was moderate, showing that polymophism rate (%P) = 56.25%, number of effective alleles (Ne) = 1.365, expected heterozygosity (He) = 0.215. Inter-population genetic difference exhibited the pairwise genetic distance using Nei’s method was 3.4%. The Analysis of molecular variance (AMOVA) showed variance within and among populations was 12% and 88%, respectively. In addition, the Principle Coordinate Analysis (PCoA) scatter showed the interaction between the populations.