Condition-dependence of the sexually dimorphic transcriptome in Drosophila melanogaster

Evolution. 2010 Jun;64(6):1836-48. doi: 10.1111/j.1558-5646.2009.00938.x. Epub 2010 Jan 6.


Sexually dimorphic traits are by definition exaggerated in one sex, which may arise from a history of sex-specific selection-in males, females, or both. If this exaggeration comes at a cost, exaggeration is expected to be greater in higher condition individuals (condition-dependent). Although studies using small numbers of morphological traits are generally supportive, this prediction has not been examined at a larger scale. We test this prediction across the transcriptome by determining the condition-dependence of sex-biased (dimorphic) gene expression. We find that high-condition populations are more sexually dimorphic in transcription than low-condition populations. High-condition populations have more male-biased genes and more female-biased genes, and a greater degree of sexually dimorphic expression in these genes. Also, condition-dependence in male-biased genes was greater than in a set of unbiased genes. Interestingly, male-biased genes expressed in the testes were not more condition-dependent than those in the soma. By contrast, increased female-biased expression under high condition may have occurred because of the greater contribution of the ovary-specific transcripts to the entire mRNA pool. We did not find any genomic signatures distinguishing the condition-dependent sex-biased genes. The degree of condition-dependent sexual dimorphism (CDSD) did not differ between the autosomes and the X chromosome. There was only weak evidence that rates of evolution correlated with CDSD. We suggest that the sensitivity of both female-biased genes and male-biased genes to condition may be akin to the overall heightened sensitivity to condition that life-history and sexually selected traits tend to exhibit. Our results demonstrate that through condition-dependence, early life experience has dramatic effects on sexual dimorphism in the adult transcriptome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Nutritional Physiological Phenomena*
  • Animals
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / metabolism*
  • Female
  • Gene Expression Profiling
  • Male
  • Oligonucleotide Array Sequence Analysis
  • Ovary / metabolism
  • Sex Characteristics*
  • Testis / metabolism