Scientists discover sex determination differs in mice and men

18 Nov 2014

Researchers from UQ’s Institute for Molecular Bioscience are one step closer to grasping what makes men ‘male’, a finding that could help us manage disorders of sex development affecting hundreds of children born each year.

“We know that mutations in the sex-determining region Y (SRY) found on the Y chromosome can affect development of the reproductive organs and genitals, but we still don’t have a good enough grasp on the sex-determination process to be able to diagnose and manage these disorders effectively,” Lead researcher Professor Koopman said.

In trying to understand this complex process, Professor Peter Koopman and fellow IMB researchers have uncovered a key difference in how SRY operates in humans compared to mice.

“We found that human SRY needs a partner protein to activate the sex-determining machinery for testis development,” Professor Koopman said.

“But mouse SRY is different; it can trigger testis development all on its own without relying on this second protein.

Now that the scientists know that human SRY, unlike mice, relies on a second partner protein to ‘trigger’ testis development, they can start to identify new causes for disorders of sex development.

“We can broaden our search for the genetic causes of disorders of sex determination, not only focusing on SRY, but on its interaction with a partner protein,” he said.

Professor Koopman was also surprised by the difference between the mouse models and humans.

“It’s amazing to think how different the sex-determining machinery is between such highly related species,” he said.

“And it is interesting from an evolutionary perspective; it’s as though mice have streamlined the process compared to humans.

“What is clear is that we still have much to learn about the finer details of how the Y chromosome makes males male,” he said.

Fellow IMB researcher Dr Liang Zhao was the first author of the study published this September in the international journal, Proceedings of the National Academy of Sciences.

The study was supported by grants from the Australian Research Council and the National Health and Medical Research Council of Australia.

For more information on IMB’s disorders of sex development research, visit

Media contact: Gemma Ward, IMB Communications Manager, (07) 3346 2134 or