Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.593069
Title: Mitochondrial DNA evolution in Canary Island lizards (genus: Gallotia)
Author: McGregor, Duncan
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 1992
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Abstract:
The evolutionary relationships of three Canary Island lizard species of the genus: Gallotia, G.stehlini, G.atlantica and G.galloti, were analysed by examining mitochondrial DNA sequence variation in eight Canary Island populations. Initially, restriction endonucleases were the method of choice for examining mitochondrial DNA variation within Gallotia. A number of fragment visualisation techniques, both radioactive and non-radioactive, were utilised during the course of the study. However, mitochondrial DNA probe hybridisation was used to examine restriction fragment length polymorphism (RFLP) for the majority of samples. The advent of the polymerase chain reaction (PCR) enabled sequence variation at two mitochondrial loci, to be studied directly. Conserved primers for regions of the cytochrome b and 12s ribosomal RNA (rRNA) genes were used to examine five hundred and forty base pairs of sequence information. As a by-product of the 12s rRNA amplification, five hundred and thirty-six base pairs of the 18s rRNA gene were also obtained. Mitochondrial genetic distance data was examined for evidence of founder effects, and for the reliability of a molecular clock in the evolution of Gallotia. In order to test the reliability of the mitochondrial DNA phylogenies, variation in nuclear DNA was also examined. RFLP analysis was carried out by 18s rRNA probe hybridisation on DNA samples digested with a number of restriction endonucleases. This analysis revealed little variation between the species examined. In addition six primers were utilised in the recently developed molecular technique: the random amplified polymorphic DNA assay (RAPD). Although the phylogenies reconstructed using this technique are supportive of the mitochondrial phylogenies, they must be treated with caution due to the possible errors inherent in this assay. The evolutionary relationships suggested by the molecular data sets were used to suggest a potential consensus phylogeny for Gallotia. The tree reconstructed was then compared to morphological phylogenies, and to the existing fossil and geological data in order to discuss a possible colonisation sequence for the species examined.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.593069  DOI: Not available
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