Sex chromosomes and speciation in Drosophila

Trends Genet. 2008 Jul;24(7):336-43. doi: 10.1016/j.tig.2008.04.007.


Two empirical rules suggest that sex chromosomes play a special role in speciation. The first is Haldane's rule - the preferential sterility and inviability of species hybrids of the heterogametic (XY) sex. The second is the disproportionately large effect of the X chromosome in genetic analyses of hybrid sterility. Whereas the causes of Haldane's rule are well established, the causes of the 'large X-effect' have remained controversial. New genetic analyses in Drosophila confirm that the X is a hotspot for hybrid male sterility factors, providing a proximate explanation for the large X-effect. Several other new findings -- on faster X evolution, X chromosome meiotic drive and the regulation of the X chromosome in the male-germline -- provide plausible evolutionary explanations for the large X-effect.

Publication types

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

MeSH terms

  • Animals
  • Drosophila / genetics*
  • Evolution, Molecular
  • Genetic Speciation*
  • Infertility
  • Male
  • Sex Chromosomes / genetics*
  • X Chromosome / genetics