Search

RFLP analysis of mitochondrial DNA (mtDNA) was used to study variation within 13 populations of #Clarias batrachus$, sampled respectively in Vietnam, Thailand and in the Indonesian Archipelago. In this study an amplified region corresponding approximately to 2.3 kilobases of the Cytochrome-b and D-loop genes was digested using 8 restriction enzymes (HinfI, Hin6I, MvaI, MspI, HaeIII, BanHI, NdeII, DraI). 12 mtDNA haplotypes were found in 40 specimens. Each sampling location was characterised by one haplotype, except Palembang (Sumatra, Indonesia) and Samarinda (Kalimantan, Indonesia) where 2 and 4 haplotypes were found respectively. The consensus tree calculated from 15 more parsimonious networks showed that mtDNA haplotypes are geographically distributed. Three well differentiated clusters were identified. The first cluster is composed by populations from both Thailand and Vietnam, the second cluster by two populations from West Sumatra between populations which come from highlands (altiude more than 1000 meters in Bukittingui, and 300 meters in Nias Island) and populations located in lowlands. The significant genetic relatedness observed between populations from Sumatra (Jambi, Palembang, Muara Tebo, Teluk Kuantan) and populations from Java indicate a possible common origin which is probably in Kalimantan. This result is supported by the high diversity of haplotypes revealed in Samarinda (Kalimantan) and their intermediate position in the genetic network. The populations from highlands in West Sumatra which share a common haplotype are genetically more related to populations from Thailand and Vietnam than to populations from the rest of Indonesia. These populations seems to be relict populations from a first colonisation event which arise from the continental part of Asia... (D'après résumé d'auteur)