Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.640554
Title: Tree-thinking, molecules and gallwasps : analysing evolutionary patterns in European gallwasps using a molecular phylogenetic approach
Author: Rokas, Antonis
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2001
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Abstract:
I have analysed data from nuclear and mitochondrial DNA sequence data in gallwasps and reviewed rare large-scale mutational changes in animals, in an attempt to understand their utility for phylogenetic analysis. Analysis of the sequence data led to the identification of fast and slow-evolving loci for insect phylogenetics. Review of published data on rare large-scale mutations (or Rare Genomic Changes - RGCs for short) suggested that RGCs are likely to be useful and low-homoplasy phylogenetic markers. Using DNA sequence and allozyme data, I studied the phylogeography and post-Pleistocene range expansion of two widely distributed European oak gallwasp species, Andricus quercustozae and Biorhiza pallida. Patterns of genetic diversity in these species have been shaped by their association with their obligate hosts, the oaks (both species), and by the bacterial endosymbiont Wolbachia (B. pallida). These studies revealed the existence of multiple distinct European and Anatolian refuges and suggested that the species’ post-glacial distribution range has been determined by the presence/absence of specific oak species in central and northern Europe. Using mitochondrial DNA sequence data, I generated a phylogeny of the various European gallwasp genera, verifying the existence of various conserved clades and suggesting that many species are non-monophyletic due to lineage sorting of ancestral polymorphisms and / or hybridisation. For a subset of this phylogeny - the genus Andricus - the evolution of shift(s) in the sexual generation oak hosts and host organs galled were analysed, using additional nuclear data. Finally, I surveyed member species of most gallwasp tribes for infection with the bacterial endosymbiont Wolbachia and showed that: (i) the prevalence of Wolbachia differs between lineages with different reproductive modes; (ii) Wolbachia is not associated with thelytoky in the cyclical parthenogenetic gallwasp lineage (in contrast, thelytoky in herb and rose gallwasps is, most likely, Wolbachia-induced); and (iii) horizontal transfer of Wolbachia is likely to have occurred between gall-inducers and their associated inquilines.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.640554  DOI: Not available
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