Genomic associations with bill length and disease reveal drift and selection across island bird populations

Armstrong, Claire, Richardson, David S., Hipperson, Helen, Horsburgh, Gavin J., Küpper, Clemens, Percival-Alwyn, Lawrence, Clark, Matt, Burke, Terry and Spurgin, Lewis G. (2018) Genomic associations with bill length and disease reveal drift and selection across island bird populations. Evolution Letters, 2 (14707 / 5745). 22–36. ISSN 2056-3744

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Abstract

Island species provide excellent models for investigating how selection and drift operate in wild populations, and for determining how these processes act to influence local adaptation and speciation. Here, we examine the role of selection and drift in shaping genomic and phenotypic variation across recently separated populations of Berthelot's pipit (Anthus berthelotii), a passerine bird endemic to three archipelagos in the Atlantic. We first characterized genetic diversity and population structuring that supported previous inferences of a history of recent colonizations and bottlenecks. We then tested for regions of the genome associated with the ecologically important traits of bill length and malaria infection, both of which vary substantially across populations in this species. We identified a SNP associated with variation in bill length among individuals, islands, and archipelagos; patterns of variation at this SNP suggest that both phenotypic and genotypic variation in bill length is largely shaped by founder effects. Malaria was associated with SNPs near/within genes involved in the immune response, but this relationship was not consistent among archipelagos, supporting the view that disease resistance is complex and rapidly evolving. Although we found little evidence for divergent selection at candidate loci for bill length and malaria resistance, genome scan analyses pointed to several genes related to immunity and metabolism as having important roles in divergence and adaptation. Our findings highlight the utility and challenges involved with combining association mapping and population genetic analysis in nonequilibrium populations, to disentangle the effects of drift and selection on shaping genotypes and phenotypes.

Item Type: Article
Faculty \ School: Faculty of Science > School of Biological Sciences
Related URLs:
Depositing User: Pure Connector
Date Deposited: 26 Jan 2018 12:30
Last Modified: 08 Sep 2020 23:52
URI: https://ueaeprints.uea.ac.uk/id/eprint/66089
DOI: 10.1002/evl3.38

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