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Molecular evolutionary studies of filarial parasites of the genus Brugia
Abstract
Lymphatic filariasis is a human parasitic disease which causes great physical suffering, while also having a substantial economic impact on the peoples of the tropics and sub-tropics. In order to collect accurate epidemiological data which are crucial for designing effective control programs, reliable diagnostic and taxonomic information is needed. The studies described here were designed to obtain DNA sequence data from specific coding and non-coding loci of the parasite genome, which could augment existing morphological, biochemical, and ecological data, to test hypotheses concerning diagnostic and taxonomic classification. Highly repeated DNA elements, members of the Hha I repeat family, were cloned, sequenced and the data employed in a phylogenetic analysis of species, sub-species and distinct geographic isolates of human filarial parasites from the genus Brugia. Comparative analysis reveals that although the 322 base pair (bp) repeat sequences between Brugia pahangi and Brugia malayi are nearly 90% identical overall, there is a small 70 bp region which contains enough divergence to clearly distinguish between these two major species. Nucleotide differences in this and other regions were exploited to draw distinctions between repeats cloned from B. timori, B. patei and various geographic isolates of B. malayi which differ in biological characteristics such as host range, vector preference and periodicity. In addition to the Hha I repeats, the gene encoding a prominent, stage-specific surface antigen from the animal parasite, Brugia pahangi was also cloned and sequenced. Homologous sequences were obtained from the related human pathogen Brugia malayi and a comparative analysis initiated. The results show that the protein coding, flanking and intervening sequences are highly conserved between the two species. In addition to its utility as a taxonomic and phylogenetic tool, the highly conserved nature of this protein sequence makes it a potential candidate for recombinant vaccine development.
Subject Area
Molecular biology|Cellular biology
Recommended Citation
Freedman, Daniel Jay, "Molecular evolutionary studies of filarial parasites of the genus Brugia" (1992). Doctoral Dissertations Available from Proquest. AAI9219432.
https://scholarworks.umass.edu/dissertations/AAI9219432