Genetic variation and differentiation in African catfish, Clarias gariepinus, assessed by heterologous microsatellite DNA

The population structure and genetic variation between Clarias gariepinus populations collected from 3 different regions of South India (Vellore, Chennai & Bangalore) were analyzed using cross species amplification of microsatellite markers developed from C. batrachus and C. macrocephalus (Cba12, Cbal7, Cmac6 & Cmac11). Samples were amplified using polymerase chain reaction (PCR). Fifty four alleles were recorded with 3 to 6 alleles per locus. Allelic frequency (Pi), observed heterozygosity (He obs), expected heterozygosity (He exp), polymorphism information content (PIC) and effective alleles were determined. Hardy-Weinberg equilibrium was checked according to the chi square (X super(2)) test and were significant at P< 0.001. Genetic differentiation and genetic diversity were evaluated by gametal correlation coefficient (Fst) and gene flow (Nm). The loci were polymorphic in all the populations. The clustering dendrogram was made based on the results of UPGMA methods using POPGENE software, which revealed the distance between three population forming two clusters; one based on Vellore and another cluster based on Chennai and Bangalore populations. Thus the present study will be useful for the analysis of population genetic diversity, and the management of this important fish resource.