Standard Article

Mammalian Sex Chromosome Evolution

  1. Gerald J Wyckoff1,
  2. Christine M Malcom2

Published Online: 15 JUL 2008

DOI: 10.1002/9780470015902.a0005792.pub2



How to Cite

Wyckoff, G. J. and Malcom, C. M. 2008. Mammalian Sex Chromosome Evolution. eLS. .

Author Information

  1. 1

    University of Missouri-Kansas City, Kansas City, Missouri, USA

  2. 2

    University of Chicago, Chicago, Illinois, USA

Publication History

  1. Published Online: 15 JUL 2008

This is not the most recent version of the article. View current version (19 SEP 2013)


Although they are highly dissimilar in sequence content in extant organisms, the mammalian sex chromosomes (i.e. the X and Y) evolved from a pair of autosomes. Differentiation of the sex chromosomes during evolution was initiated by the suppression of X–Y recombination. This was followed by the general degeneration of genes on the Y-chromosome, with specific instances of gene specialization on the nonrecombining portion of the Y.


  • X-chromosome;
  • Y-chromosome;
  • mammalian sex chromosomes;
  • Y degeneration;
  • pseudoautosomal region;
  • nonrecombining Y