Molecular discrimination of six species of Bagrid catfishes from Indus river system using randomly amplified polymorphic DNA markers.

Bagrid catfishes constitute a very important group of fishes having immense commercial importance in south-east countries. The phylogenetic relationships and genome specificity among six species of Bagrid catfishes (Mystus bleekeri, M. cavasius, M. vittatus, M. tengara, M. aor and M. seenghala) were investigated using RAPD markers as discriminating characters for the first time. 511 RAPD fragments were generated using ten decamer primers of arbitrary nucleotide sequences. Amplification reactions resulted in fragments ranging in length between 92 and 2,863 bp, which were assigned to 155 RAPD loci. Clearly resolved and repeatable bands were scored for their presence or absence in a binary matrix. Different RAPD profiles were observed for all the six Mystus species. In the present study three group diagnostic, eleven group exclusive and 18 species-specific markers were generated. Thus six Mystus species can be successfully differentiated on the basis of these 18 species-specific RAPD markers. UPGMA dendrogram constructed on the basis of genetic distance formed two distinct clusters, M. seenghala and M. aor form one separate cluster from other four species i.e., M. tengara, M. cavasius, M. bleekeri and M. vittatus. The inferences drawn from the above study clearly showed their genetic distinctness from the other four Mystus species and supported their inclusion into a separate genus, Sperata.