Primary sex determination

Duration: 8min 43sec Views: 1040 Submitted: 22.07.2020
Category: Mature
Sex determination refers to the mechanisms employed by organisms to produce offspring that are of two different sexes. First we present an overview of the sex determination mechanisms used by mammals. Then we discuss the great variety of mechanisms used by animals other than mammals. A developing mammalian embryo's gender is determined by two sequential processes known as primary and secondary sex determination. Early in an embryo's development four weeks after fertilization, in humans , two groups of cells become organized into the gonad rudiment that will eventually develop into either the ovaries or testicles. These gonads will eventually be the source of gametes in the adult.

The Role of H-Y Antigen in Primary Sex Determination

Sex-determination system - Wikipedia

Metrics details. Primary sex determination in placental mammals is a very well studied developmental process. Here, we aim to investigate the currently established scenario and to assess its adequacy to fully recover the observed phenotypes, in the wild type and perturbed situations. Computational modelling allows clarifying network dynamics, elucidating crucial temporal constrains as well as interplay between core regulatory modules. Relying on a comprehensive revision of the literature, we define a logical model that integrates the current knowledge of the regulatory network controlling this developmental process. Our analysis indicates the necessity for some genes to operate at distinct functional thresholds and for specific developmental conditions to ensure the reproducibility of the sexual pathways followed by bi-potential gonads developing into either testes or ovaries. Our model thus allows studying the dynamics of wild type and mutant XX and XY gonads.

Molecular mechanisms involved in mammalian primary sex determination

Sex determination refers to the developmental decision that directs the bipotential genital ridge to develop as a testis or an ovary. Genetic studies on mice and humans have led to crucial advances in understanding the molecular fundamentals of sex determination and the mutually antagonistic signaling pathway. In this review, we summarize the current molecular mechanisms of sex determination by focusing on the known critical sex determining genes and their related signaling pathways in mammalian vertebrates from mice to humans. We also discuss the underlying delicate balance between testis and ovary sex determination pathways, concentrating on the antagonisms between major sex determining genes.
The basic embryonic plan of mammals is inherently feminine. Male development is due to two-step interventions of this basic plan: the Y chromosome directs the embryonic indifferent gonad to organize a testis instead of an ovary; the Y-organized testis synthesizes and secretes testosterone, which induces all the extragonadal masculine development. The Y chromosome plays no direct and appreciable role in extragonadal masculine development.