Which gene is responsible for the production of a protein that causes the development of the testes?

The SRY gene, located on the Y chromosome, is crucial for the development of the testes. It encodes a transcription factor that initiates the process of male sex differentiation. During embryonic development, the presence of the SRY gene activates various other genes that lead to the formation of the testes from the indifferent gonadal tissue. The testes then produce testosterone and other hormones that promote the development of male characteristics and reproductive structures.

In contrast, the XX gene does not play a significant role in determining male or female characteristics, while the Y chromosome, although it houses the SRY gene, is more of a structural entity that contains several genes involved in male development. The MAOA gene is associated with the metabolism of neurotransmitters and has no direct connection to reproductive organ development. Thus, the SRY gene is specifically pivotal in triggering the biological pathways necessary for developing testes.