The development of sexual dimorphism: studies of the Caenorhabditis elegans male

Wiley Interdiscip Rev Dev Biol. Jul-Aug 2014;3(4):239-62. doi: 10.1002/wdev.136. Epub 2014 May 13.


Studies of the development of the Caenorhabditis elegans male have been carried out with the aim of understanding the basis of sexual dimorphism. Postembryonic development of the two C. elegans sexes differs extensively. Development along either the hermaphrodite or male pathway is specified initially by the X to autosome ratio. The regulatory events initiated by this ratio include a male-determining paracrine intercellular signal. Expression of this signal leads to different consequences in three regions of the body: the nongonadal soma, the somatic parts of the gonad, and the germ line. In the nongonadal soma, activity of the key Zn-finger transcription factor TRA-1 determines hermaphrodite development; in its absence, the male pathway is followed. Only a few genes directly regulated by TRA-1 are currently known, including members of the evolutionarily conserved, male-determining DM domain Zn-finger transcription factors. In the somatic parts of the gonad and germ line, absence of TRA-1 activity is not sufficient for full expression of the male pathway. Several additional transcription factors involved have been identified. In the germ line, regulatory genes for sperm development that act at the level of RNA in the cytoplasm play a prominent role.

Publication types

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

MeSH terms

  • Animals
  • Caenorhabditis elegans / embryology
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / physiology
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Male
  • Sex Characteristics*
  • Sex Determination Processes*
  • Sex Differentiation*
  • Spermatozoa / metabolism
  • Spermatozoa / physiology
  • Testis / embryology
  • Testis / metabolism
  • Testis / physiology
  • Transcription Factors / genetics
  • Transcription Factors / metabolism


  • Caenorhabditis elegans Proteins
  • DNA-Binding Proteins
  • Transcription Factors
  • tra-1 protein, C elegans