Feminization of complex traits in Drosophila melanogaster via female-limited X chromosome evolution* |
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Authors: | Katrine K. Lund-Hansen Jessica K. Abbott Edward H. Morrow |
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Affiliation: | 1. Department of Biology, Section for Evolutionary Ecology, Lund University, Lund, 223 62 Sweden;2. Department of Environmental and Life Sciences, Karlstad University, Karlstad, 651 88 Sweden |
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Abstract: | A handful of studies have investigated sexually antagonistic constraints on achieving sex-specific fitness optima, although exclusively through male-genome-limited evolution experiments. In this article, we established a female-limited X chromosome evolution experiment, where we used an X chromosome balancer to enforce the inheritance of the X through the matriline, thus removing exposure to male selective constraints. This approach eliminates the effects of sexually antagonistic selection on the X chromosome, permitting evolution toward a single sex-specific optimum. After multiple generations of selection, we found strong evidence that body size and development time had moved toward a female-specific optimum, whereas reproductive fitness and locomotion activity remained unchanged. The changes in body size and development time are consistent with previous results, and suggest that the X chromosome is enriched for sexually antagonistic genetic variation controlling these particular traits. The lack of change in reproductive fitness and locomotion activity could be due to a number of mutually nonexclusive explanations, including a lack of sexually antagonistic variance on the X chromosome for those traits or confounding effects of the use of the balancer chromosome. This study is the first to employ female-genome-limited selection and adds to the understanding of the complexity of sexually antagonistic genetic variation. |
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Keywords: | Drosophila melanogaster experimental evolution intralocus sexual conflict sex chromosomes sexual antagonism |
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