Use of restriction fragment length polymorphisms (RFLPs) to distinguish between nematodes of pathogenic significance

Abstract

SUMMARYThe availability of restriction fragment length polymorphisms (RFLPs) would be useful for studying the extent of diversity among morpholgically indistinguishable populations of filarial parasites. Such polymorphisms may be useful in correlating various physiological and clinical differences with parasite heterogeneity. In order to identify such RFLPs, we isolated DNA from microfilaria of 6 filarial species (Acanthocheilonema viteae, Brugia malayi, Brugia pahangi, Dirofilaria immitis, Litomosoides carinii and Setaria digitatum), digested the DNA with several restriction endonucleases, prepared Southern blots and probed with 32 P-labelled DSA probes. The patterns of fragments generated using two restriction endonucleases, Mbo I and Taq I, in combination with two probes, rDNA from the free-living soil nematode Caenorhabditis elegans, and pBM103, an anonymous DNA probe from B. malayi, unequivocally distinguish between all 6 of the species. To ensure that the differences we observed between the species represent true interspecies variation rather than fortuitous individual variations we analysed DNA from several individual B. malayi and B. pahangi worms. The individual B. malayi worms demonstrated restriction profiles that were invariant, as did the individual B. pahangi worms, demonstrating that the differences we observed were true interspecies variations.

Repetitive DNA and hybridization patterns demonstrate extensive variability between the sibling species Globodera rostochiensis and G. pallida

“…The differences observed in the number of repetitive DNA bands between G. rostochiensis and G. pallida suggest a dissimilar organization in the number, size and/or arrangement of repetitive DNA sequence families. Striking differences between sibling species have been reported before (McLain, Rai & Fraser, 1987;Majiwa & Webster, 1987;Cameron et al 1988). In D. melanogaster the amount of repetitive DNA is 7-fold greater than in the sibling species D. simulans (Dowsett & Young, 1982).…”

Genetic analyses of Chinese isolates of Toxoplasma gondii reveal a new genotype with high virulence to murine hosts

“…These archetypal strains are typically identified by techniques such as restriction fragment length polymorphism (RFLP) (Pena et al, 2008) or microsatellite analysis (Lehmann et al, 2006). These techniques have been widely used for genotyping a broad range of organisms (Anderson et al, 2000;Cameron et al, 1988;Hide and Tait, 2009;Widmer et al, 2004;Severson et al, 1995). In addition, use of these methods has identified other minor subpopulations of T. gondii, e.g.…”

Restriction fragment length polymorphisms of Anisakinae larvae

“…Coding sequences, e.g. rDNA, tend to be highly conserved in the course of evolution and the spacer sequences between the coding regions of the ribosomal cistrons tend to diverge rapidly, which accounts for the distinctive species-specific restriction fragments (CAMERON et al, 1988). Thus, the RFLPs produced by the hybridization of 25s rRNA transcripted from the coding region of rDNA may possibly be able to show not only the differences between species but may also be used in estimating the genetic distances in related species.…”