Purifying Selection in Corvids Is Less Efficient on Islands

Abstract Theory predicts that deleterious mutations accumulate more readily in small populations. As a consequence, mutation load is expected to be elevated in species where life-history strategies and geographic or historical contingencies reduce the number of reproducing individuals. Yet, few stud...

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Bibliographic Details
Published in:Molecular biology and evolution 2020-02, Vol.37 (2), p.469-474
Main Authors: Kutschera, Verena E, Poelstra, Jelmer W, Botero-Castro, Fidel, Dussex, Nicolas, Gemmell, Neil J, Hunt, Gavin R, Ritchie, Michael G, Rutz, Christian, Wiberg, R Axel W, Wolf, Jochen B W
Format: Article
Language:English
Subjects:
avian genomics
comparative analysis
Discoveries
distribution of fitness effects
molecular evolution
mutation load
selection
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Summary:Abstract Theory predicts that deleterious mutations accumulate more readily in small populations. As a consequence, mutation load is expected to be elevated in species where life-history strategies and geographic or historical contingencies reduce the number of reproducing individuals. Yet, few studies have empirically tested this prediction using genome-wide data in a comparative framework. We collected whole-genome sequencing data for 147 individuals across seven crow species (Corvus spp.). For each species, we estimated the distribution of fitness effects of deleterious mutations and compared it with proxies of the effective population size Ne. Island species with comparatively smaller geographic range sizes had a significantly increased mutation load. These results support the view that small populations have an elevated risk of mutational meltdown, which may contribute to the higher extinction rates observed in island species.
ISSN:0737-4038
1537-1719
1537-1719
DOI:10.1093/molbev/msz233