Sex differentiation -- gonadogenesis and novel genes

During embryogenesis, most organ rudiments differentiate into only one type of organ and functional mutations are normally lethal for the embryo. However, the indifferent gonad has two options, to form either a testis or an ovary, and mutations of this tissue usually produce sex reversal or sterility which is not lethal for the individual. Therefore, gonadal development serves as an excellent model system for investigating questions of cell fate and organogenesis. The studies of human patients showing different types of sex reversal, in combination with the use of transgenic mice and/or gene targeting disruption, have led to the isolation of several genes important for sex development. These include SRY/Sry, encoding the testis-determining factor, Ftz-F1 encoding steroidogenic factor 1 (SF-1) and Wilms' tumor gene (WT-1). However, the mammalian sex differentiation pathway requires the function of a number of additional genes which we are now trying to identify with the help of mRNA differential display technique.