Comparative phylogeography of the catshark, Haploblepharus pictus and its nematode parasite, Proleptus obtusus
Year: 2011
Type: dissertation
Abstract: The comparative phylogeography of the host-parasite relationship of the southern African endemic dark shyshark, Haploblepharus pictus and its nematode parasite, Proleptus obtusus was investigated.To date, no studies have been conducted on the population structure of catsharks and their species specific parasites and little is known about the population dynamics of these species.A total of 116 catsharks and 201 parasites were analysed from seven South African localities.The mitochondrial marker COI was used and species specific primers were designed for both the host and parasite.Haplotype networks were constructed and no strong geographically structured groupings were found for either species.Pairwise Φ st values for the parasite and host found Gansbaai to be significantly differentiated from the other sites.Fu's F s were significantly negative for both host and parasite indicating population disequilibrium.Proleptus obtusus displayed a pattern of population expansion which was confirmed by the mismatch distribution.Mismatch distributions failed to indicate population expansion for the sharks.Other factors such as selection, migration or genetic drift are likely the cause of the population disequilibrium detected.Interestingly, no barrier to gene flow was found around Cape Point, a known break for other species such as the clinid, Clinus cottoides and the caridean shrimp Palaemon peringueyi.The outcome of this study suggests that levels of gene flow in H. pictus are high enough to suggest that the documented site fidelity is not as strong as originally proposed.The parasite, being dependent on the host, shows a similarly high level of gene flow among sampling sites.
Author: Ann McLachlan
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2147637327