MOLECULAR PHYLOGENETIC STUDIES ON BRUGIA-FILARIAE USING HHA-I REPEAT SEQUENCES

This paper is the first molecular phylogenetic study on Brugia parasit es (family Onchocercidae) which includes 6 of the 10 species of this g enus : B. beaveri Ash et Little, 1964; B. buckleyi Dissanaike et Param ananthan, 1961; B. malayi (Brug, 1927) Buckley, 1960; B. pahangi, (Buc kley ei Edeson, 1956) Buckley, 1960; B. patei (Buckley, Nelson et Heis ch, 1958) Buckley, 1960 and B. timori Partono ef al., 1977. Hha I repe at sequences are 322 nucleotides long, highly repeated, tandemly arran ged and unique to the nuclear genomes of the genus Brugia. Hha I repea t sequence data was collected by PCR, cloning and dideoxy sequencing. The Hha I repeal sequences were aligned and analyzed by maximum parsim ony algorithms, distance methods and maximum likelihood methods to con struct phylogenetic trees. Bootstrap analysis was used io test the rob ustness of the different phylogenetic reconstructions. The data indica ted that the Hha I repeat sequences are highly conserved within specie s yet differ significantly between species. The various tree-building methods gave identical results. Bootstrap analyses on the Hha I repeat sequence data set identified al least two clades : the B. pahangi-B. beaveri clade and the B. malayi-B.timori-B, buckleyi clade; the First clade includes parasites of carnivores from Asia and America; the seco nd includes species from primates and lagomorphs from Asiatic region. ii was also noted that the Hha repeat sequences obtained from B. malay i were identical to those obtained from B. timori, indicating very rec ent speciation.