Premium
Determination of temperature sensitive stages for sexual differentiation of the gonads in embryos of the turtle, Emys orbicularis
Author(s) -
Pieau Claude,
Dorizzi Mireille
Publication year - 1981
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1051700308
Subject(s) - chelydra , biology , sexual differentiation , turtle (robot) , developmental stage , embryo , sexual maturity , stage (stratigraphy) , andrology , anatomy , zoology , endocrinology , microbiology and biotechnology , ecology , genetics , medicine , psychology , developmental psychology , gene , paleontology
In order to determine the temperature sensitive stages for sexual differentiation of the gonads in Emys orbicularis , eggs of this turtle were shifted at different stages of embryonic development from the male‐producing temperature of 25°C to the female‐producing temperature of 30°C and reciprocally. Based on the series of developmental stages described by Yntema (′68) for Chelydra serpentina , temperature begins to influence sexual differentiation of Emys orbicularis at stage 16, a stage in which the gonads are still histologically undifferentiated. Its action lasts over the first steps of histological differentiation of the gonads. The minimal exposure at 25°C required for male differentiation of all individuals extends from stage 16 to somewhat before stage 21. For 100% female differentiation, incubation at 30°C must be longer, from stage 16 to somewhat before stage 22. Shorter exposures at 25°C or 30°C during these periods result in different percentages of males, females, and intersexes. Our results show that there is a critical stage (stage 16) which is the same for both male and female differentiation of the gonads. The thermosensensitive periods are rather long, corresponding to 11–12 days at 25°C and 30°C.