Smooth muscle-epithelial interactions in normal and neoplastic prostatic development. Such alleles would drop out of the population of males early in their lifetime because of embryonic lethalitywhereas other alleles might drop out of the population of females because of sensitivity to female-enhanced factors.
Dams were killed by inhalation of carbon dioxide and subsequent cervical dislocation.
In some species alternative morphs, or morphotypeswithin one sex exist, such as flanged larger than females, with large flap-like cheek-pads and unflanged about the same size as females, no cheek-pads male orangutans and sometimes differences between male morphs can be more noticeable than differences between a male and a female within such species.
However, recent studies suggest that brain sex chromosomes directly affect the sexual differentiation of certain types of behavior and physiology. Similarities Typical studies on sex differentiation in mammals in Bedfordshire 1 Sex differentiation of core sexual behavior is mainly induced by the exposure of gonadal hormones during development Arnold and Chen, ; Maekawa et al.
Gonads are histologically distinguishable by 6—8 weeks of gestation. Studies have shown that the specific chemicals called endocrine disruptors can influence sexual differentiation in many species Colborn et al. It is possible that a mild rejection occurred in Japanese quail chimeras that had a female karyotype in the forebrain and male karyotype in the rest of their body.
XXY mice phenotypically male, but sterile without germ cells.
Infertility in male aquatic invertebrates: a review. Double treatment, consisting of either estrogen or testosterone during hatching and testosterone at the adult stage, enables females to sing Gurney and Konishi,indicating that the presence of estrogen in the brain during development can masculinize the song-related nuclei.
Namespaces Article Talk. Organizing action of prenatally administered testosterone propionate on the tissues mediating mating behavior in the female guinea pig. Zoological Journal of the Linnean Society. Based on observations in the FCG mouse model, the investigators reported that the latency and frequency of copulatory behavior are somewhat influenced by sex chromosomes Park et al.
Androgens play a vital role in Wolffian duct WD development, but the mechanisms that underlie this are unknown. A great deal of further work is needed to clarify the separate and interacting effects of multiple sex-biasing mechanisms highlighted in the theory of sexual differentiation.
This was associated with reduced cell proliferation, but there was no increase in apoptosis or change in expression of androgen receptor mRNA or protein. If a follicle is not formed, the oogonia degenerate.