Démonstration génétique de l'inversion fonctionnelle du phénotype sexuel femelle sous l'action de la température d'élevage chez l'Amphibien Urodèle : Pleurodeles waltlii Michah

Abstract

Genetic demonstration of functionalsex inversion in Pleurodeles waltlii Michah. (urode% amphibian) under the effect of temperature. Rearing standard Pleurodeles waltlii at ambient temperature always leads to a female to male sex ratio of 1 :1 (639 p-617 d ; 20 matings). Larvae known to be of ZW female sex genotype were reared at 30 °C for 4 months (from stage 33 to 2 months after metamorphosis). When they were adult, the majority (11 out of 15) displayed all the characters of male sexual maturity (heat-induced ZW neo-males). These neo-males were functional. The offspring were analysed at ambient temperature. When heat-induced ZW neo-males were bred with ZW standard females, the sex of the offspring conformed to the theoretical expectation of 3 females to 1 male (691 9-247 d ; 14 matings). Some females from the preceding matings displayed the new WW genotype. When they were mated with ZZ standard males, the offspring were 100 % phenotypic females (587 9 ; 5 matings). Breeding heat-induced ZW neo-males with WW females gave 100 % phenotypic females (201 9 ; 2 matings). These results provide the first irrefutable genetic demonstration of temperature sex-reversal in tetrapode vertebrates. Introduction.