SRY Gene
- In sexual reproduction in humans, a sperm from a male fuses with, or fertilises, an egg from a female to form a zygote, which then develops into an embryo
- To begin with the embryo develops in the same way regardless of its sex, and embryonic gonads develop that will either become ovaries in females or testes in males
- The factor that determines whether the embryonic gonads will develop into ovaries or testes is the presence or absence of a single gene known as the SRY gene
- The SRY gene is located on the Y chromosome, meaning that is only present in roughly 50% of embryos
- The SRY gene codes for a DNA-binding protein known as TDF, or testis determining factor, which stimulates the expression of further genes responsible for the development of testes
- If the SRY gene is present in the embryo's DNA, the embryonic gonads will develop into testes
- If the embryo has two X chromosomes, and therefore the SRY gene is not present in its DNA, the embryonic gonads will develop into ovaries