Temperature-dependent sex determination: Upregulation of SOX9 expression after commitment to male development

Patrick S. Western, Jenny L. Harry, Jennifer A.M. Graves, Andrew H. Sinclair

Research output: Contribution to journalArticleResearchpeer-review

Abstract

In mammals, birds and reptiles the morphological development of the gonads appear to be conserved. This conservation is evident despite the different sex determining switches employed by these vertebrate groups. Mammals exhibit chromosomal sex determination (CSD) where the key sex determining switch is the Y-linked gene, SRY. Although SRY is the trigger for testis determination in mammals, it is not conserved in other vertebrate groups. However, a gene closely related to SRY, the highly conserved transcription factor, SOX9, plays an important role in the testis pathway of mammals and birds. In contrast to the CSD mechanism evident in mammals and birds, many reptiles exhibit temperature dependent sex determination (TSD) where the egg incubation temperature triggers sex determination. Here we examine the expression of SOX9 during gonadogenesis in the American alligator, (Alligator mississippiensis), a reptile that exhibits TSD. Alligator SOX9 is expressed in the embryonic testis but not in the ovary. However, the timing of SOX9 upregulation in the developing testis is not consistent with a role for this gene in the early stages of alligator sex determination. Since SOX9 upregulation in male embryos coincides with the structural organization of the testis, SOX9 may operate farther downstream in the vertebrate sex differentiation pathway than previously postulated.

Original languageEnglish
Pages (from-to)171-177
Number of pages7
JournalDevelopmental Dynamics
Volume214
Issue number3
DOIs
Publication statusPublished - 17 Mar 1999

Keywords

  • Gonadogenesis
  • Reptile
  • SOX9
  • Temperature-dependent sex determination
  • Testis differentiation

Cite this

Western, Patrick S. ; Harry, Jenny L. ; Graves, Jennifer A.M. ; Sinclair, Andrew H. / Temperature-dependent sex determination : Upregulation of SOX9 expression after commitment to male development. In: Developmental Dynamics. 1999 ; Vol. 214, No. 3. pp. 171-177.
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Temperature-dependent sex determination : Upregulation of SOX9 expression after commitment to male development. / Western, Patrick S.; Harry, Jenny L.; Graves, Jennifer A.M.; Sinclair, Andrew H.

In: Developmental Dynamics, Vol. 214, No. 3, 17.03.1999, p. 171-177.

Research output: Contribution to journalArticleResearchpeer-review

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