PHYLOGENETIC ANALYSIS OF CICHLID FISHES USING NUCLEAR-DNA MARKERS

The recent explosive adaptive radiation of cichlids in the great lakes of East Africa has attracted the attention of both morphologists and molecular biologists. To decipher the phylogenetic relationships among the various taxa within the family Cichlidae is a prerequisite for an swering some fundamental questions about the nature of the speciation process. In the present study, we used the random amplification of pol ymorphic DNA (RAPD) technique to obtain sequence differences between s elected cichlid species. We then designed specific primers based on th ese sequences and used them to amplify template DNA from a large numbe r of species by the polymerase chain reaction (PCR). We sequenced the amplified products and searched the sequences for indels and shared su bstitutions. We identified a number of such characters at three loci-D XTU1, DXTU2, and DXTU3-and used them for phylogenetic and cladistic an alysis of the relationships among the various cichlid groups. Our stud ies assign an outgroup position to Neotropical cichlids in relation to African cichlids, provide evidence for a sister-group relationship of tilapiines to the haplochromines, group Cyphotilapia frontosa with th e lamprologines of Lake Tanganyika, place Astatoreochromis alluaudi to an outgroup position with respect to other haplochromines of Lakes Vi ctoria and Malawi, and provide additional support for the monophyly of the remaining Lake Victoria haplochromines and the Lake Malawi haploc hromines. The described approach holds great promise for further resol ution of cichlid phylogeny.