Thesis (MSc)--University of Stellenbosch, 2006. / ENGLISH ABSTRACT: An understanding of the phylogeography and evolutionary processes involved in
speciation is essential for the conservation and management of any particular
species. To investigate the phylogeographic patterns in Agama atra from the Cape
Fold Mountains (CFM), 98 individuals from 38 geographically close localities
were analysed. In addition, to understand the phylogeographic associations
between the CFM populations and the rest of Southern Africa, 18 specimens from
12 localities outside the CFM were also included. A total of 988 characters
derived from two mitochondrial DNA fragments (control region and ND2)
revealed 59 distinct haplotypes in the CFM. Parsimony, Bayesian and maximum
likelihood analyses revealed four distinct clades associated with geography within
the CFM. These clades were supported by a haplotype network and were defined
as the Cape Peninsula clade, the Limietberg clade, the northern CFM clade and
the central CFM clade. Analysis of molecular variance confirmed the high degree
of genetic structure within the CFM, with more than 75% of genetic variation
found among the geographic areas. SAMOVA and nested clade analysis (NCA)
suggest that the central CFM clade may be more diverse than detected by the
networks and the phylogenetic analyses. The processes that caused the four
distinct genetic groups in the CFM are not yet clear. Using a speculative
molecular clock estimate, the main cladogenesis of A. atra within the CFM took
place, approximately ~6.5 - 9 MYA. This dating coincides well with the
documented Miocene-Pliocene climate fluctuations which might have contributed
towards the isolation among lineages. The genetic structure found in A. atra is
also markedly congruent with what has been found in other taxa such as Mesamphisopus spesies, Potamonautes brincki, and Pedioplanis burchelli and
this would further support vicariance as a main isolating factor here. / AFRIKAANSE OPSOMMING: ‘n Goeie begrip van die filogeografie en die evolusionêre gebeurtenisse wat
verband hou met spesiasie is belangrik vir die bewaring en bestuur van enige
spesie. Om die filogeografiese patrone in Agama atra van die Kaapse Plooiberge
(KPB) te ontleed, was 98 individue van 38 nabygeleë lokaliteite geanaliseer.
Tesame met bogenoemde monsters was 18 individue van 12 lokaliteite van buite
die KPB ook geanaliseer om die filogeografiese verwantskappe tussen die KPB
bevolkings en die res van Suidelike Afrika te ondersoek. Uit ‘n totaal van 988
karakters verkry uit twee mitochondriale DNS fragmente (die kontrole gebied en
ND2) is 59 haplotipes gevind. Parsimonie en modelgebaseerde filogenetiese
analises dui daarop dat vier groepe geassosieer met geografie binne die KPB
voorkom. Die groepe word geondersteun deur ‘n haplotipe netwerk en word soos
volg gedefinieer: ‘n Kaapse Peninsula groep, ‘n Limietberg groep, ‘n noordelike
KPB groep en ‘n sentrale KPB groep. Analises van molekulêre variansie
(AMOVA) bevestig die hoë graad van genetiese struktuur binne die KPB, met
meer as 75% genetiese variasie gevind tussen die geografiese areas. SAMOVA en
gesetelde groep analises (“NCA”) stel voor dat die sentrale KPB groep dalk meer
variasie vertoon as wat die netwerk en filogenetiese analises vertoon. Die prosesse
wat die vier genetiese groepe tot stand gebring het is nog nie bekend nie. Volgens
‘n spekulatiewe molekulêre klok berekening het die hoof kladogenese van A. atra
binne die KPB ongeveer ~6.5 - 9 miljoen jaar (MJ) gelede plaasgevind. Hierdie
datering stem goed ooreen met die gedokumenteerde Mioseen-Plioseen klimaat
veranderinge wat isolasie van die groepe kon bewerkstellig het. Die genetiese
struktuur van A. atra in the KPB is ook gevind in ander taksa soos Mesamphisopus spesies, Potamonautes brincki, en Pedioplanis burchelli en
bevestig dus dat vikariansie hier die hoof faktor vir isolasie is.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/21762 |
| Date | 04 1900 |
| Creators | Swart, Belinda |
| Contributors | Matthee, C.A., Tolley, K.A., 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 | 88 leaves : ill. |
| Rights | Stellenbosch University |
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