Parentage Analysis of the Progenies of the Reciprocal Crosses of Pangasianodon hypophthalmus (Sauvage, 1878) and Clarias gariepinus (Burchell, 1822) using Cytochrome b Gene

In this study, parentage analysis of the progenies from reciprocal crosses of Pangasianodon hypophthalmus (PH) and Clarias gariepinus (CG) was accomplished by sequencing the cytochrome b gene and running phylogenetic analysis. The result obtained showed that the nucleotide composition of the cytochrome b gene of the reciprocal hybrid crosses exhibited high (99 %) similarity with those of the maternal parents notwithstanding the different morphology within the hybrid pool (i.e. Panga-like and Clarias-like). The analysis of 1076bp of the cytochrome b gene using three methods for inferring molecular relationships (Maximum Likelihood, Neighbour Joining, and Maximum Parsimony) revealed two main clusters. The upper cluster was a mix of C. gariepinus and the two distinct progenies of ♀CG × ♂PH (i.e. Panga-like and Clariaslike), while the lower cluster was a mix of the P. hypophthalmus and the progenies of ♀PH × ♂CG (i.e. Panga-like only). Hence, despite, phenotypic differences within the hybrid pool, progenies still inherit cytochrome b gene from the maternal parent alone. As a result, the direction of crosses of the reciprocal crosses could be accurately determined.