Figure 5 .

Changes in the sex-determining gene of O. luzonensis. (A) Evolutionary history up to the appearance of Gsdf^Y. Dmy appeared as a common ancestor of O. latipes, O. curvinotus, and O. luzonensis. Gsdf^Y appeared in, and Dmy disappeared from, the ancestor of O. luzonenesis. (B) Change in the sex-determining cascade. (Top) Sex-determining cascade in an ancestor of O. luzonensis. (Bottom) Current sex-determining cascade in O. luzonensis. Gsdf was downstream of Dmy. A mutation then occurred in Gsdf, allowing its expression without Dmy. Gsdf^Y then became the new sex-determining gene.