Temperature‐dependent sex determination: A mechanistic approach

Academic Article


  • A variety of sex determination systems exists in reptiles, including temperature‐dependent sex determination (TSD). While the precise physiological basis of TSD is unknown, numerous past studies have provided a general characterization of this phenomenon. The period of thermosensitivity encompasses the middle one third to one half of embryonic development. It has been shown that in several species of reptiles this period starts prior to (histologically defined) gonadal differentiation and extends to a time when sex specific changes are becoming evident in the gonads. During the thermosensitive period, sex determination is sensitive to both the magnitude and duration of a given incubation temperature. Further, the treatment of developing eggs with specific steroid hormones (in particular, estrogens) has been shown to override the effects of male‐producing temperatures and induce female sex determination. This has led to a variety of studies investigating whether the production of estrogens may be naturally involved in TSD. The results from several studies are consistent with the hypothesis that temperature could be affecting endogenous estrogen production by controlling the production of aromatase. However, the results from other studies are not consistent with this hypothesis. Current studies by a variety of research laboratories are now addressing the estrogen hypothesis as well as TSD in general at various physiological and molecular levels. As such, these studies should provide a wealth of data on the physiological basis of TSD. © 1994 Wiley‐Liss, Inc. Copyright © 1994 Wiley‐Liss, Inc., A Wiley Company
  • Authors

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    Digital Object Identifier (doi)

    Author List

  • Wibbels T; Bull JJ; Crews D
  • Start Page

  • 71
  • End Page

  • 78
  • Volume

  • 270
  • Issue

  • 1