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Title: Evolutionary and conservation genetics of the Seychelles warbler (Acrocephalus sechellensis)
Author: Wright, David J.
ISNI:       0000 0001 2427 6878
Awarding Body: University of East Anglia
Current Institution: University of East Anglia
Date of Award: 2014
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In this thesis, I investigated how evolutionary forces and conservation action interact to shape neutral and adaptive genetic variation within and among populations. To accomplish this, I studied an island species, the Seychelles warbler (Acrocephalus sechellensis), with microsatellite markers and major histocompatibility complex (MHC) genes as measures of neutral and adaptive variation respectively. First, I used museum DNA and historical records to reveal a recent bottleneck that provides context for the contemporary genetic variation observed in this species. I then determined the impact of four translocations on genetic diversity over two decades. I found that diversity does not differ significantly between islands but the use of smaller founder sizes in two translocations has caused population divergence. These results indicate that stochastic genetic capture is important in translocations and that future assisted gene flow between populations may be necessary. As a tool for conservation practitioners, I wrote a technical report of the most recent translocation - to Frégate Island - detailing practicalities and outcomes to help inform future translocation policy. Using two translocation events as experiments, I then tested whether MHC-based social mate choice acts to maintain MHC diversity in the Seychelles warbler, finding that male age and heterozygosity, but not MHC, predicted pairing success. Lastly, I investigated survival and reproductive consequences of Ase-ua4, an MHC class I allele previously shown to confer a survival advantage in the Seychelles warbler. I found widespread patterns of allele frequency increase within cohorts consistent with the survival effect, but no overall increase in population allele frequency over time. I investigated potential antagonistic reproductive mechanisms, but found no clear evidence for why this allele is not driven towards fixation. Collectively, my results provide an interesting case study of the evolutionary conservation approach, whilst providing insight into the importance of maintaining genetic variation in natural populations.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available