Molecular evidence supports a genic capture resolution of the lek paradox

• Published in: Nature communications 2019-03, Vol.10 (1), p.1359-1359, Article 1359
• Main Authors: Dugand, Robert J., Tomkins, Joseph L., Kennington, W. Jason
• Format: Article
• Language: English
• Subjects: 45; 45/23; 631/181/2470; 631/181/2474; 631/181/2475; 64; 64/24; Animal reproduction; Animals; Divergence; Drosophila melanogaster - genetics; Female; Fruit flies; Genetic diversity; Genetic variance; Genetic Variation; Genome, Insect; Genomes; Humanities and Social Sciences; Hypotheses; Lek; Male; Mating Preference, Animal; Models, Genetic; multidisciplinary; Mutation; Phenotype; Reproduction - genetics; Science; Science (multidisciplinary); Selection, Genetic; Sexual selection
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-09371-y

The genic capture hypothesis, where sexually selected traits capture genetic variation in condition and the condition reflects genome-wide mutation load, stands to explain the presence of abundant genetic variation underlying sexually selected traits. Here we test this hypothesis by applying bidirectional selection to male mating success for 14 generations in replicate populations of Drosophila melanogaster . We then resequenced the genomes of flies from each population. Consistent with the central predictions of the genic capture hypothesis, we show that genetic variance decreased with success selection and increased with failure selection, providing evidence for purifying sexual selection. This pattern was distributed across the genome and no consistent molecular pathways were associated with divergence, consistent with condition being the target of selection. Together, our results provide molecular evidence suggesting that strong sexual selection erodes genetic variation, and that genome-wide mutation-selection balance contributes to its maintenance. Females are choosy about their mates, which should erode genetic diversity but in practice does not. Here, selection and genomic resequencing of Drosophila supports the hypothesis that this paradox can be explained by sexually selected traits reflecting genetic variation in condition.