It's part-reptile, part-mammal, part-bird – and totally unique. Two centuries after European scientists deemed a dead specimen so outlandish it had to be a fake, the bizarre genetic secrets of Australia's platypus has been laid bare.

Platypuses lay eggs and produce venom like some reptiles, but they sport furry coats and feed their young with milk like mammals. The odd creatures are classed as monotremes, with only one close relative – the echidna.

And while the gene that the human sex-determining gene evolved from is present in the platypus genome, it seems to have nothing to do with sex determination. So, that function must have evolved after the platypus split from our common ancestor, about 166 million years ago.

"It looks like the platypus started from the same suite of genes, but did completely different things with them," says Graves.

The draft genome sequence should also help to end the platypus's identity crisis, Graves says.