A gene that is responsible for creating male genitalia in a female embryo has been identified by scientists.
Melbourne researcher Professor Andrew Sinclair, of the Murdoch Childrens Research Institute and the University of Melbourne, found that a gene involved in brain development is implicated in disorders of sex development (DSD).
The team of researchers found that mutations affecting the SOX3 gene caused it to be abnormally turned on in the embryonic gonad, leading to testis development in human DSD patients and mice.
Simply put, male glands are formed due to the Y chromosome known as SRY, which is absent in females.
"Surprisingly, we found that the SOX3 gene could substitute for the SRY gene in XX female embryos, resulting in the development of testes, male genitalia and a masculine appearance in these patients," said Sinclair.
The find will not only help explain the XX cases of DSD, but also provide new insight into the evolution of the SRY gene, which is thought to have evolved from the SOX3 gene.
They believe that the mutations of the SOX3 gene must have occurred millions of years ago, causing the SOX3 gene to be turned on in the gonad and initiate testis development.
The study appears in the journal of Clinical Investigation.