Saturday, January 09, 2021

Duck-billled platypus' genome is as weird as you might expect

I have read several articles recently about the duck-billed platypus, that weirdest-of-the-weird animal from Down Under, the one with the bill and webbed feet of a waterbird, the venomous ankle-spikes, the biofluorescent fur, and the ten sex chromosomes (unlike every other mammal, which have just two), that lays eggs but still feeds its young on its milk (even if it happens to secrete it through sweat glands!), and hunts using electroreception (emitting electrical impulses to locate objects in the water).

It is such a strange beast that it appears to be a random mish-mash of several different animals, the closest thing we have to a real-life chimera. The latest information we have gleaned (and the reason for the recent proliferation of articles), shows that that is actually not that far off the truth.

Researchers at the University of Copenhagen have now mapped the complete genome of the platypus, as well as that of the only other living monotreme, the short-beaked echidna. Monotremes are unrelated to any other living mammal, having split away from other mammals as long ago as 170 million years, a time when the early dinosaurs were colonizing the earth, and millions of years before other modern mammals emerged. The duck-billed platypus in particular appears to have genes similar to both mammals and birds, and even some otherwise found only in reptiles.

This report comes almost a year after another groundbreaking study of platypuses, which suggests that this weird and wonderful animal may be "on the path to extinction", and could see its population halved by 2070 as a result of development and the effects of climate change (particularly droughts).

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