FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

The Nile tilapia (Oreochromis niloticus niloticus Linnaeus, 1758), Mozambique tilapia (O. mossambicus Peters, 1852), Blue tilapia (O. aureus Steindachner, 1864), Wami tilapia (O. urolepis hornorum Trewavas, 1966) and Sabaki tilapia (O. spilurus spilurus Günther, 1894), stocked at Freshwater Aquaculture Research Center, were identified by using of PCR-RFLP technique. For these 5 species of tilapia, the length of D-loop region in mitodhondrial DNA was at the range of 958 ~ 968 base-pairs (bp), A+T (%) of the base composition was at the range of 64.3 ~ 65.5, percent identity was between 88.5 and 96.2, and genetic distance were between 0.038 and 0.124.Digestion of the D-loop region, by using AcuI, BbsI and MspI restriction enzymes, resulted in several different restriction patterns that could be used to discriminate the five tilapia species. Phylogenetic tree constructed by neighbor-joining (NJ) method showed that Wami tilapia and Mozambique tilapia were in the same clade, Nile tilapia and Sabaki tilapia were in another clade, and Blue tilapia was alone.