A dosage-sensitive reversal of this process occurs with duplication of Dax-1, which acts during this process as a dominant negative regulator of a class of nuclear receptors including SF-1. A key protein in this process relies on a feedforward loop with prostaglandin D2 and FGF9 to maintain its production and lends its name to the SOX genes. Mutations in 21-hydroxylase cause a disease whose classic form is characterized by either salt-wasting or an abnormal version of this embryonic process, congenital (10[1])adrenal hyperplasia. The paramesonephric ducts develop and the mesonephric ducts regress in a version of this process that occurs in the absence of AMH. Two distinct disorders of this process are caused by deletions or translocations of SRY. For 10 points, Turner’s syndrome is a disorder of what process, whose result is classically determined by the presence of XX or XY chromosomes? ■END■