[Contribution of experimental intersexuality in chickens to the problem of gonadal differentiation and its abnormalities in amniotic vertebrates].

The grafting of embryonic testes to chick embryos realizes an experimental model which is near the spontaneous situation of the cattle "free-martin". It allows to obtain a masculinization of female host embryos developing in some cases up to a total and definitive reversal of sex differentiation. Indeed, it is possible, by this way to obtain testes induced under the influence of substance(s) secreted by the grafts which determine epigenetically a sexual phenotype opposite to the genotype of the host embryos.

[Crossed graft of embryonic testis between quail and chick embryos: contribution to the study of the mechanism of female bird embryo masculinization].

Quail, or chick embryonic testes grafted respectively in the extraembryonic coelom of chick or quail embryos induce both a Mullerian duct regression and a masculinization of the female host gonads up to the differentiation of two testes, in some cases. Such a result confirms the fact evidenced previously in other bird species (chick and duck) that the testis-inducer is interspecific. Quail cells are not observed in histological sections of embryonic gonads of testis-grafted chicks.

Influence of heterospecific testis graft on the gonadal sex differentiation of female bird embryos.

Testes from duck and chick embryos grafted, respectively, to chick and duck genetically female host embryos modifies their gonadal differentiation. It results in masculinization developing, in some cases as far as testis formation. This demonstrates 'in vivo' that the testis inductor(s) secreted by the grafted testis is (are) interspecific.

[Dynamics and karyotyping of a population of wild boar with clear colored fur].

The population of wild boars living in the wood of Chize contains 25 % of animals having a clear coloured fur. Chromosomal study of these, don't reveal any anomaly of number or structure of their chromosomes. This modification seems be due to a genic mutation and not to an eventual hybridization with domestic pigs.

[Influence of an antiandrogen, cyproteron acetate, on the morphogenesis of the epididymis in the chick].

Morphogenesis of the epididymis, which takes place in the chick, during the two months after hatching, is inhibited by the antiandrogenic drug, cyproteron acetate, which acts as strongly as castration. This fact is a good argument for our conception of sexual differentiation after which epididymis is induced by testosterone.