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Title: Genetics of plumage colour polymorphism in the Gouldian finch (Erythrura gouldiae)
Author: Zhang, Hanyuan
ISNI:       0000 0004 5364 6630
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2015
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External pigmentation plays an important role in the evolution, ecology and behaviour of birds. However, our understanding of the genetic basis of variation in plumage colouration is as yet very limited, and especially for loci that control carotenoid pigmentation. Therefore, this thesis details the exploration of the molecular genetic basis of head colour polymorphism that occurs in natural populations of the Gouldian finch (Erythrura gouldiae). In order to identify the genomic regions encoding variation in plumage traits, a microsatellite-based genetic linkage map was constructed. There was a high degree of synteny throughout the microsatellite map between Gouldian finch and the zebra finch genome assembly. Restriction site associated DNA (RAD) sequencing was then used in a genome-wide association study (GWAS) in an attempt to identify the genomic location of the Yellow locus responsible for determining the yellow-headed/red-headed colour polymorphism. A candidate region on chromosome 8 was discovered to contain significant allele frequency differences. Subsequently, using the candidate gene approach, haplotypes co-segregating with different phenotypes were identified in the CYP2J2-2 gene on an unassembled section of zebra finch chromosome 8. This result suggests that the CYP2J2-2 gene is associated with this carotenoid-based polymorphism. From the linkage map of chromosome 8, a 2.9-Mb region also showed evidence of association with the yellow/red polymorphism. The available sample size was limited so these results need to be confirmed by testing more samples. Additionally, the hypothesis, based on a previous study, was tested and rejected that the melanin-based polymorphism determined by the Gouldian finch Red locus was caused by an inversion. In summary, this thesis identified a candidate region for the Yellow locus and provides an empirical foundation for the future study of the genetic mechanism and molecular evolution of plumage colour polymorphism in the Gouldian finch.
Supervisor: Burke, Terry Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available