ABSTRACT
In the developing embryo with a genetic complement of 46 XY, it is the presence of the Y chromosome that determines that the undifferentiated gonad will become a testis (Fig. 3.1). Absence of the Y chromosome will result in the development of an ovary. On the short arm of the Y chromosome is a region known as the SRY gene, which is responsible for the determination of testicular development as it produces a protein known as testicular determining factor (TDF). TDF directly influences the undifferentiated gonad to become a testis. When this process occurs, the testis also produces Müllerian inhibitor.
