Mitochondrial DNA polymorphism within and among species of Capillaria sensu lato from Australian marsupials and rodents

The nucleotide variation in a mitochondrial DNA (mtDNA) fragment within and among species of Capillaria sensu lato from Australian marsupials and rode nts was analyzed using a mutation scanning/sequencing approach. The fragmen t of the cytochrome c oxidase subunit I (COI) was amplified by PCR from par asite DNA, and analysed by single-strand conformation polymorphism (SSCP) a nd sequencing. There was no significant variation in SSCP profiles within a morphospecies from a particular host species, but significant variation ex isted among morphospecies originating from different host species. The same morphospecies was found to occur in 1-3 tissue habitats within one host in dividual or within different individuals of a particular species of host fr om the same or different geographical areas, and morphospecies appeared to he relatively host specific at the generic level. The results indicated tha t the species of Capillaria sensu lato examined, although highly variable i n their host and tissue specificity, may exhibit the greatest degree of spe cificity at the level of host genus. (C) 2000 Published by Elsevier Science Ltd. on behalf of Australian Society for Parasitology Inc. All rights rese rved.