[The genes in the molecular cascade of the mammalian sexual development]

The sex of an individual is established as a consequence of molecular events that occur in the complex genetic cascade. During sexual development, morphological changes are closely associated with the action of genes expression of which is tightly regulated according to the genetic program. Recently, a number of genes that are involved in this process have been isolated. WT-1 and SF-1 are required for the early formation of the gonadal primordium. SRY is the switch to start the male sexual differentiation by triggering the Sertoli cell lineage. An autosomal gene SOX9, which can cause the sex reversal, might also be involved in the male sex determination. SF-1 is a key factor for the male sexual differentiation, regulating the expression of MIS and the synthesis of testosterone in the fetal testis. DAX1 might be responsible for the female sexual development. The mutation or abnormal expression of these regulatory genes and their downstream genes can cause a variety types of the sex reversal and/or malformation of the gonad and the internal and external genitalia.