Thesis (MSc (Botany and Zoology))--Stellenbosch University, 2011. / ENGLISH 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 st values for the parasite and host found Gansbaai to be
significantly differentiated from the other sites. Fu’s Fs 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. / AFRIKAANSE OPSOMMING: Die vergelykende filogeografie van die gasheer-parasiet verhouding tussen die endemiese
suider-Afrikaanse donker skaamhaai, Haploblepharus pictus en sy nematode parasiet,
Proleptus obtusus is ondersoek. Huidiglik is daar nog geen ander studies uitgevoer met
betrekking tot die populasie struktuur van skaamhaaie en hul spesies-spesefieke
parasiete nie en min is bekend oor die populasie dinamiek van hierdie spesies. In hierdies
studie is ‘n totaal van 116 skaamhaaie en 201 parasiete vanaf sewe lokaliteite
geanaliseer. Die mitikondriale merker COI is hiervoor gebruik en spesie spesefieke
inleiers is vir beide gasheer en parasiet ontwerp. Haplotipe netwerke is saamgestel vir
beide spesies en het geen duidelike geografies gestruktureerde groepe aangedui nie.
Paarsgewyse st waardes van beide parasiet en gasheer het daarop gedui dat Gansbaai
geneties gedifferensieerd is van alle ander lokaliteite. Fu se Fs was statisties betekenisvol
met ‘n negatiewe waarde vir beide spesies, wat dui op populasie disekwilibrium. Proleptus
obtusus het ‘n patroon van populasie groei getoon, wat deur Fu se Fs en die misparing
verspreiding bevestig is. Die misparing verspreiding het nie populasie toename vir die
skaamhaaie aangedui nie. Die waargeneemde populasie disekwilibrium is waarskynlik die
gevolg van seleksie, migrasie of genetiese drywing. Geen genetiese breuk is by Kaap
Punt, wat ‘n genetiese breuk vir verskeie ander spesies soos Clinus cottoides en
Palaemon peringueyi is, gevind nie. Die uitkomstes van hierdie studie stel voor dat vlakke
van geen vloei in H. picuts hoog genoeg is om ‘n patroon van genetiese vermenging
tussen lokaliteite, op die mitokondriale DNS vlak, tot gevolg te hê. Dit beteken moontlik
dat die gedokumenteerde gebied gebondenheid van hierdie spesie nie so sterk, soos
oorspronklik voorgestel, is nie. Die parasiet, waarskynlik aangesien hy van sy gasheer
afhanklik is, toon ‘n soortgelyke hoë vlak van geen vloei tussen lokaliteite. Dus toon beide
spesies ‘n algehele afwesigheid van genetiese struktuur, met die isolasie van Gansbaai
van alle ander lokaliteite.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/18106 |
| Date | 12 1900 |
| Creators | McLachlan, Ann |
| Contributors | Matthee, Conrad A., Von der Heyden, Sophie, Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | x, 53 p. : ill., maps |
| Rights | Stellenbosch University |
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