What the platypus' sexual evolution can tell us about our own

The platypus has already revolutionised our understanding of the origin of our sex chromosomes, showing they emerged after the separation of the monotremes from other mammals. Photo / Supplied

Our most distant relative, the platypus, has a lot to teach us about sex and evolution.

University of Adelaide's Associate Professor Frank Grutzner says it's played a key role in giving new insight into how the regulation of the entire genome has changed during mammalian evolution over the past 200 million years.

Dr Grutzner is part of a study that used new technology to reveal all the genes active in tissues, including the brain, testes, kidney, heart and liver in different species, including humans, chicken, mice, opossum and platypus.

The study showed there were more changes across the species in some tissues like the testes, than other tissues, such as the brain.

"That reinforces the idea that there is a faster pace of evolution, if you like, in the testes than in the brain," he said.

Dr Grutzner says the platypus has already revolutionised our understanding of the origin of our sex chromosomes, showing they emerged after the separation of the monotremes from other mammals.

"The inclusion of the platypus as our most distant mammalian relative was particularly important in this study," he said.

"One gene that shows much higher activity in the platypus brain is known to be involved in explorative behaviour in mice and it is tempting to speculate that this has to do with the intense foraging style that we can observe in the platypus.

"If you look at the genes that have, for example, something to do with detox in the liver, and they have all changed in the platypus or the human, may be something happened in these organs and these tissues, and in the physiology of these tissues that is causing the change."

He says the study and the database of information will allow connections to be made between some of the physiology, tissue, anatomy and the actual genes that underlie.

"And that's a very important starting point for any further study," he said.

The international study, led by University of Lausanne associate professor Henrik Kaessmann, is published in the journal Nature.

- AAP