Genetic characterisation and molecular identification of two morphologically similar species of whiting, Sillago sihama (Forsskål, 1775) and Sillago vincenti McKay, 1980

Abstract

Two morphologically similar species of whiting, Sillago sihama and Sillago vincenti were genetically characterised on the basis of their RAPD profiles, 12s and 16s rDNA sequences and their PCR-RFLP profiles. The RAPD profiles, developed by three random primers, OPA-12, OPB-12 and OPF-17, revealed 52.63% polymorphic loci in S. vincenti and 31.58% in S. sihama. The average genetic diversity within species (Hs) was 0.188±0.1574 and Gst (coefficient of gene differentiation) was 0.4397. Average genetic divergence between species was 0.4397, as expected for two different species of a genus. Partial 12s and 16s rDNA sequences were amplified and sequenced from both species, using primers reported previously for brackishwater fish species. Distance measure showed more differences between the 12s rDNA sequences (D=0.135) compared to the 16s rDNA (D= 0.0742). Digestion of 12s rDNA amplicon with Hind III and digestion of 16s rDNA with Sma I generated distinct PCR-RFLP profiles for the two species and that can be used for the identification of the species