Differentiation of two Pangasius species, Pangasius krempfi and Pangasius mekongensis using inter- simple sequence repeat markers

Abstract

Pangasius krempfi and Pangasius mekongensis are economically important species of catfish family Pangasiidae. Compared to P. mekongensis, P. krempfi has higher values and has been cultured recently in the Mekong Delta, Viet Nam. Wild catfish fingerlings (<10 grams) caught in Mekong estuaries consist of both species, which are hardly distinguishable using morphological methods. This study aimed to search for effective Inter-simple sequence repeat (ISSR) markers that can be used to quickly identify these two species. Samples were collected in different locations of the lower Mekong River. Six primers with clear and species-specific bands were selected to analyze 11 samples per species. Totally, 62 bands were detected with a size range from 500 bp to 2400 bp, in which 22 and 31 private bands were found in P. krempfi and P. mekongensis, respectively. Nei’s genetic distance between the two species was 0.742 and their genetic difference GST was 0.655. Principal coordinates analysis showed that the two species clustered in two separate groups. The results indicate that six ISSR markers used in the present study can differentiate P. krempfi and P. mekongensis.