Platypus genetic code unravelled

A patchwork of genes derived from birds, reptiles and mammals has made the duck-billed platypus one of nature's oddest creations, research has shown.

Scientists from around the world worked together to draw up the first blueprint of the platypus genetic code.

Published in the journal Nature, it shines a light on the early history of mammals, when furry animals had reptilian features.

The duck-billed platypus, a native of Australia, is classified as a mammal because it produces milk and has a coat of fur.

But the platypus also lays eggs - one of only two mammals, known as monotremes, to do so. It also sports a duck-like bill equipped with a sophisticated electrosensory system used to forage for food underwater, and males possess a pair of hind leg spurs that can deliver a powerful venom.

The new genome sequence was constructed from DNA taken from a female platypus named Glennie, collected from a river at Glenrock Station, New South Wales, Australia.

When European experts first laid eyes on a duck-billed platypus sent from Australia in the 19th century, they assumed it was a hoax.

In fact the platypus had been following its own peculiar evolutionary path since diverging from the rest of the mammalian lineage 166 million years ago.

Analysis of the creature's genome - its complete genetic "code book" - revealed that the platypus shares 82% of its genes with humans, mice, dogs, opossums and chickens.

Genes were found both for egg-laying, a feature of reptiles and birds, and producing milk, a distinctly mammalian characteristic. Although the platypus lacks nipples, its young suckle milk through the creature's abdominal skin.

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