Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: In southern Africa, the ticks Amblyomma hebraeum and Hyalomma rufipes are the main vectors
of animal Heartwater and human Crimean Congo Haemorragic Fever, respectively. In order to
investigate the phylogeographic structure of these ectoparasites, population genetic studies were
conducted throughout southern and partly eastern Africa. Knowing the levels of genetic diversities and
population connectivities throughout the species’ native ranges, may be useful for implementing
control measures (cross country borders for example), evaluate the potential for drug resistance in
introduced locations as well as for elucidating its vectorial capacities in the region. Mitochondrial
cytochrome oxidase I (COI) and the internal transcriber spacer 2 (ITS-2) sequences were obtained from
eleven sampled localities. In general, haplotype networks and molecular diversity values showed
significant genetic structure between most of the sampled populations. Fu’s Fs and mismatch
distributions suggested recent population expansions following a bottleneck. A Mantel regression
analysis also revealed a significant isolation by distance for H. rufipes. Comparing the two species, H.
rufipes showed much stronger signals of geographic genetic population structure in relation to A.
hebraeum. A single taxonomic unit is suggested for A. hebraeum while H. rufipes is characterized by
the existence of at least three distinct genetic assemblages that may point to incipient speciation. The
difference between the two species may be explained by gene flow restriction within the region, by the
number of hosts required to complete the life cycle (2 and 3 hosts, respectively), type of host species
(domestic and wild animals; small and big mammals, birds) and its availability, and host species
overlap. Also, a geographic break between possible host species during the Pleistocene, domestication
of animals and climatic conditions in the region played a role on the genetic structure of H. rufipes. / AFRIKAANSE OPSOMMING: Die suider Afrikaanse bosluise, Amblyomma hebraeum en Hyalomma rufipes is die hoof
vektore van Hartwater in diere en Crimean Kongo Haemorargiese koors in mense. Om die
filogeografiese struktuur van hierdie ektoparasiete te ondersoek, is bevolking-genetiese studies
uitgevoer in suidelike Afrika asook gedeeltelik in oos Afrika. Deur die vlakke van genetiese diversiteit
en bevolkingsverbindings regdeur die spesies se natuurlike verspreiding te weet, sal dit dalk moontlik
wees om: beheermaatreëls (byvoorbeeld oorgrens) in te stel, die waarskynlikheid van
weerstandbiedendheid in nuut losgelate gebiede te verstaan, en meer insigte in die vektoriale kapasiteit
te verkry. Mitochondriale sitochroom oksidae (COI) en die interne transkriberende spasieerder 2 (ITS-
2) basisnukleotiedopeenvolgings van elf bevolkings is versamel. Haplotiepe netwerke en molekulêre
diversiteitwaardes het in die algemeen, betekenisvolle genetiese verkille tussen meeste van die
versamelde bevolkings aangetoon. Fu’s Fs en gemiste-paringverspreidings het voorgestel dat die
bevolkings onlangs uitgebrei het nadat hulle 'n bottelnek ondergaan het. 'n Mantel regressie analise het
ook betekenisvolle isolasie met afstand aangetoon vir H. rufipes. As die twee spesies vergelyk word het
H. rufipes baie sterker seine van genetiese geografiese bevolkingstruktuur gewys as A. hebraeum. 'n Enkele taksonomiese eenheid word voorgestel vir A. hebraeum terwyl H. rufipes gekarakteriseer word
deur ten minste drie taksonomiese eenhede. Die verskil tussen die twee spesies kan moontlik verklaar
word deur geen-vloeibeperkings in die gebied, die aantal gasheer spesies wat benodig word om die
lewenssiklus te voltooi (2 of 3 gashere onderskeidelik), tipe gasheer (domestikeerd- of wildlewend;
klein of groot soogdiere, voëls) en hulle beskikbaarheid, en die gasheerspesies se oorvleueling. Dit is
ook moontlik dat 'n geografiese breek tussen moontlike gasheerspesies gedurende die Pleistoseen,
domestikering van diere en klimaatstoestande in die streek 'n rol kon speel by die genetiese struktuur
van H. rufipes. / The NRF and the University of Stellenbosch for funding and bursary
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/20376 |
| Date | 03 1900 |
| Creators | Cangi, Nidia Michelle Muller |
| Contributors | Matthee, Conrad A., Horak, Ivan G., 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 | English |
| Type | Thesis |
| Format | x, 95 p. : ill. |
| Rights | Stellenbosch University |
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