The SRY gene is a gene located on the Y chromosome. It has a major role in directing the sexual determination of the embryo towards the male path. Insights with Professor Dominique Bonneau, geneticist.
What is the SRY gene?
SRY stands for “Sex-determining region of Y chromosome”. This is a gmajor ene in the process of sexual differentiation human embryos – and those of mammals in general – towards the development of the male reproductive system. Since 1905, we have known that the sexual determination of mammals depends on the X and Y chromosomes: males have an XY chromosome formula while females are XX. However, it was not until 1989 that the major involvement of the SRY gene was discovered.
Role: what is the SRY gene used for in humans?
The SRY gene has a primordial role in process of sexual differentiation. At the start of development embryonicit is impossible to differentiate between the female and male genitalia: “the gonads are said to be undifferentiated”. From around the 7th week, the SRY gene produces a TDF protein. (Test Determining Factor). This only leads to a genetic and hormonal cascade in XY embryos which directs the development of the genital tract in a male direction. On the other hand, female embryos (XY) which do not have the Y chromosome and therefore do not have the SRY gene, have development of their genital tract in the female direction.
Where is the SRY gene located?
The SRY gene is located on the short arm of the Y chromosome.
SRY gene dysfunctions
In some people the SRY gene may be either absent or carrying mutations which make it non-functional, or still transposed on the X chromosome. These anomalies lead to variations in sexual differentiation. For example, people in whom the SRY gene is transposed onto the X chromosome have an XX chromosomal formula but their sex determination is male. However, this is incomplete leading to infertility.
Thanks to Professor Dominique Bonneau, geneticist at Angers University Hospital.