The Variety of Vertebrate Mechanisms of Sex Determination

Table 1

The role of estrogen in sex determination of vertebrates and phylogenetic distance (adopted from [12]).

Group of vertebrata	Distance from mammals (million years ago, MYR)	Influence of estrogen on sex determination
Nonmammalian vertebrata
Pisces	450–530	+
Amphibia	300	+
Reptilia	290	+
Aves	216–199	+
Theria
Monotremata	180	+
Marsupialia	160	+
Eutheria (Mammalia)	0	—