R. Dorazi et al., OPPOSITE SEX DETERMINATION OF GONADS IN 2 PLEURODELES SPECIES MAY BE DUE TO A TEMPERATURE-DEPENDENT INACTIVATION OF SEX-CHROMOSOMES, The Journal of heredity, 86(1), 1995, pp. 28-31
In the urodele amphibians Pleurodeles waltl and Pleurodeles poireti, a
rise from 20 degrees C to 30 degrees C-32 degrees C of rearing temper
ature of larvae, when their gonads are still undifferentiated, leads t
o sex reversal: the primordial gonads differentiate into testes in P.
waltl ZW genotypic females and into ovaries in P. poireti ZZ genotypic
males. in both cases, sex-reversed gonads produce fertile spermatozoa
or oocytes. On the basis of results from intra- and interspecific cro
sses, we conclude that sex reversal appears to segregate in the presen
ce of peptidase-1 beta but not peptidase-1A. We propose that a heat-ac
tivated sequence is localized in the vicinity of the peptidase-1 beta
gene, which was demonstrated to be linked to W chromosome in P. waltl
and to Z chromosome in P. poireti. This thermosensitive locus could ac
t as a cis-inhibitor of sex determining genes during the heat treatmen
t of larvae.