‘SRY is just one way of kicking off the pathway, but you can do it by really almost any one of these sex-determining genes,’ Graves explained, blowing my mind just a little bit more. ‘That is the weirdest thing about sex. There are so many ways of doing it and they look to be quite different, but they’re actually not. They all have to do with this pathway of sixty genes. So, the pathways are similar. But it’s a completely different trigger.’ The platypus genome also revealed something else to Graves: the Y chromosome is losing genetic material.
