Arrest of sex-specific adaptation during the evolution of sexual dimorphism in Drosophila

Nat Ecol Evol. 2018 Sep;2(9):1507-1513. doi: 10.1038/s41559-018-0613-4. Epub 2018 Jul 30.

Abstract

Sexually antagonistic selection arises when a trait expressed in both sexes (a shared trait) is selected towards different, sex-specific optima. Sex-discordant selection causes different alleles to be favoured in each sex (intralocus sexual conflict). A key parameter responsible for generating this conflict is the intersexual genetic correlation (rMF), which determines the degree to which heritable genetic variation for the shared trait produces a similar phenotype in both sexes. A strong, positive rMF interferes with adaptation when there is sex-discordant selection. In principle, the rMF can evolve in response to sex-discordant selection: the faster it declines, the faster the resolution of intralocus sexual conflict. Here, we use Drosophila melanogaster to quantify the time scale over which a strong, positive rMF impedes a response to sex-discordant selection for a canonical quantitative trait (body size) with an exceptionally long (250 generations) selection experiment for a complex multicellular organism. We found that, compared with rapid and substantial evolution under sex-concordant selection, a high rMF arrested sex-specific adaptation for 100 generations in females and a minimum of 250 generations in males. Our study demonstrates that a high rMF can lead to a protracted period of adaptive stalemate during the evolution of sexual dimorphism.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Biological Evolution
  • Body Size*
  • Drosophila melanogaster / anatomy & histology*
  • Female
  • Male
  • Sex Characteristics*