Inbreeding removes sex differences in lifespan in a population of Drosophila melanogaster
Pau Carazo, Jared Green, Irem Sepil, Tommaso Pizzari, Stuart Wigby
Published 28 June 2016.DOI: 10.1098/rsbl.2016.0337
Source/Fonte: The Conversation
Abstract
Sex differences in ageing rates and lifespan are common in nature, and an enduring puzzle for evolutionary biology. One possibility is that sex-specific mortality rates may result from recessive deleterious alleles in ‘unguarded’ heterogametic X or Z sex chromosomes (the unguarded X hypothesis). Empirical evidence for this is, however, limited. Here, we test a fundamental prediction of the unguarded X hypothesis in Drosophila melanogaster, namely that inbreeding shortens lifespan more in females (the homogametic sex in Drosophila) than in males. To test for additional sex-specific social effects, we studied the lifespan of males and females kept in isolation, in related same-sex groups, and in unrelated same-sex groups. As expected, outbred females outlived outbred males and inbreeding shortened lifespan. However, inbreeding-mediated reductions in lifespan were stronger for females, such that lifespan was similar in inbred females and males. We also show that the social environment, independent of inbreeding, affected male, but not female lifespan. In conjunction with recent studies, the present results suggest that asymmetric inheritance mechanisms may play an important role in the evolution of sex-specific lifespan and that social effects must be considered explicitly when studying these fundamental patterns.
Ethics
The research conducted (under project numbers: PIEF-GA-2010-273010 and CGL2014-58722-P) complies with the ASAB/ABS ethical guidelines and with all applicable national and international legislation.
Data accessibility
Data are available from the Dryad digital repository: http://dx.doi.org/10.5061/dryad.pp6k7.
Authors' contributions
P.C. and T.P. conceived the study; P.C., T.P. and S.W. designed the study; P.C., J.G., I.S. and S.W. carried out the laboratory work; P.C. and J.G. analysed the data; P.C., J.G., T.P., I.S. and S.W. drafted the manuscript or revised it critically. All authors approve the final form of manuscript and agree to be held accountable for its content.
Competing interests
The authors declare that they have no competing interests.
Funding
This work was supported by the Marie Curie FP7 programme (PIEF-GA-2010-273010 to P.C.), by the Spanish Government (CGL2014-58722-P to P.C.) and by the Biological Sciences Research Council (BBSRC; BB/K014544/1 to S.W.).
Received April 22, 2016. Accepted June 8, 2016.
© 2016 The Authors.
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Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.
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