Genetic divergence between two clinostomatid fish endoparasites, inferred from allozyme and RAPD data

Abstract

We used allozyme and RAPD-derived data to analyse genetic divergence between Clinostomum complanatum and Neutraclinostomum intermedialis. Allozyme results showed an average heterozygosity of 4.04% in the former species and 0.7% in the latter, and with extreme divergence between the two species with fixation for alternative alleles in five out of 13 loci screened. Genetic distance and fixation index values between the two species were 0.921 and 0.920 respectively. Results from random amplified polymorphic DNA (RAPD) fingerprinting revealed additional genetic diversity within species (genetic similarities 0.742 and 0.829) and confirmed considerable divergence between the two clinostomatid species (genetic similarity 0.559). The results obtained suggest reproductive isolation between the two species and convincingly nullify earlier attempts to synonymise them.