A wide array of sex determination mechanisms, encompassing genetic and non-genetic pathways (i.e., hormonal, environmental, and epigenetic factors), have been found among different organisms. The presence of two complementary sexes, male and female, is an ancient feature in biology. Triggering the differentiation of male and female reproductive organs is a conserved ontogenic process, and sex determination is an inherently fascinating process. Sex determination is dependent on molecular signaling whether the male and the female differentiating pathway is activated, and different triggering elements such as genetic, non-genetic, and epigenetic factors control the whole process. This chapter describes various aspects of sex determination, such as historical development, the evolution of sex chromosomes, and different sex determination systems in other organisms.
Part of the book: Genetic Polymorphisms