The evolution of sex-biased genes and sex-biased gene expression

Nat Rev Genet. 2007 Sep;8(9):689-98. doi: 10.1038/nrg2167. Epub 2007 Aug 7.


Differences between males and females in the optimal phenotype that is favoured by selection can be resolved by the evolution of differential gene expression in the two sexes. Microarray experiments have shown that such sex-biased gene expression is widespread across organisms and genomes. Sex-biased genes show unusually rapid sequence evolution, are often labile in their pattern of expression, and are non-randomly distributed in the genome. Here we discuss the characteristics and expression of sex-biased genes, and the selective forces that shape this previously unappreciated source of phenotypic diversity. Sex-biased gene expression has implications beyond just evolutionary biology, including for medical genetics.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Chromosome Mapping
  • Codon / genetics
  • Evolution, Molecular*
  • Female
  • Gene Dosage
  • Gene Expression Regulation*
  • Genes, X-Linked*
  • Genes, Y-Linked*
  • Humans
  • Male
  • Open Reading Frames / genetics
  • Selection, Genetic
  • Sex Characteristics*
  • Sex Chromosomes / physiology


  • Codon