Sex determination and gonadal sex differentiation in the chicken model

Abstract

Our understanding of avian sex determination and gonadal development is derived primarily from the studies in the chicken. Analysis of gynandromorphic chickens and experimental chimeras indicate that sexual phenotype is at least partly cell autonomous in the chicken, with sexually dimorphic gene expression occurring in different tissue and different stages. Gonadal sex differentiation is just one of the many manifestations of sexual phenotype. As in other birds, the chicken has a ZZ male: ZW female sex chromosome system, in which the male is the homogametic sex. Most evidence favours a Z chromosome dosage mechanism underling chicken sex determination, with little evidence of a role for the W..