The need to detect genetic variation has fueled the development of novel marker systems in fisheries biology. In this study, a simple, fast and cost effective method was used to differentiate between species of freshwater fishes focusing on Malaysian freshwater fishes by employing
Restriction Fragment Length Polymorphisms (RFLPs) analysis of a 470-bp cytochrome b mtDNA segment. RFLP analysis using six restriction enzymes (AluI, BamHI, BsuRI, Csp61, HpaII and SalI) found variations in the digestion profile among most of the fish samples analyzed. Diagnostic digestion profiles were observed among the Hampala fishes, especially between H. macrolepidota and the other Hampala species/forms (using BsuRI and Csp61). Diagnostic digestion profiles were also detected between H.
bimaculata Type A and Type B (using AluI, BamHI, BsuRI and SalI), supporting their status as distinct species. Additionally, unique digestion profiles were observed in other species such as Leptobarbus hosii (Csp61), Osteocheilus hasseltii (Csp61), Osteocheilus sp. (Csp61), Puntioplites bulu (Csp61), Puntius bramoides (AluI), P. sealei (AluI) and Helostoma temmincki (AluI and Csp61), which can be used as genetic markers for discriminating these species. Overall, the RFLP analysis of the cytochrome
b mtDNA segment has proven to be a considerably effective, fast and non-expensive technique to discriminate among several freshwater fish species in Malaysia.