Genetic differentiation and immunogenetics of two sympatric storm petrel species on the Azores

McCubbin, Alexandra 2021. Genetic differentiation and immunogenetics of two sympatric storm petrel species on the Azores. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

This thesis investigates genetic differentiation, mate choice and immunogenetics in two recently diverged species of storm petrels breeding on the Azores – the geographically widespread H. castro and the Azores endemic H. monteiroi. Previous work found the two species largely distinct for mitochondrial and nuclear loci, but the degree of reproductive isolation or breeding time switching between the two seasonally separated taxa remains unclear. In chapter 2, a method for rapid and cost-effective screening for mitochondrial clade membership was developed, tested, and applied to both species. The method did not reveal any mismatches between presumed sample identity and mitochondrial clade, but future application may do so, allowing further investigation of the biology and genomics underlying mismatches. In chapter 3, a method for PCR amplification of Major Histocompatibility Complex (MHC) DAB loci was developed, demonstrating the retention of an ancient duplication of the MHC Class IIB region in both species. In chapter 4, this method was used for high-throughput sequencing of family trios from both species. A bioinformatic allele filtering pipeline was developed, revealing 65 DAB1 and 27 DAB2 alleles across both species (individuals for DAB1/DAB2: H. castro n=111/110; H. monteiroi n= 99/91). DAB1 was more variable than DAB2 within each species, and the ‘vulnerable’ Azores endemic H. monteiroi was found to exhibit similar immunogenetic variability as H. castro, suggesting that variability has been retained despite recent declines in H. monteiroi. Extensive signals of incomplete lineage sorting were found for DAB alleles of both species, likely reflecting balancing selection and their recent speciation. Nevertheless, DAB allele sharing between the two was limited, and multi-locus analyses found them to be clearly differentiated for MHC genotypes. This thesis contributes valuable molecular insights into the ecology and evolutionary history of H. castro and H. monteiroi, including a comprehensive characterisation of their immunogenetic variability and differentiation.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Biosciences
Subjects:	Q Science > Q Science (General)
Date of First Compliant Deposit:	3 November 2021
Last Modified:	03 Nov 2022 02:30
URI:	https://orca.cardiff.ac.uk/id/eprint/145286

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