The platypus: a living quilt of genetic oddities
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We always knew platypuses--or platypi--were weird. After all, they have mole’s fur, a duck’s bill and venomous spurs on their legs. But now we know what a pastiche of mammalian, avian and reptilian features they really are, thanks to a recent genetic mapping project by a team of international scientists:
There are genes for egg laying -- evidence of the animals’ reptilian roots. Genes for making milk, which the platypus does in mammalian style despite not having nipples. Genes for making snake venom, which the animal stores in its legs. And there are five times as many sex-determining chromosomes as normal. ‘It’s such a wacky organism,’ said Richard Wilson, director of the genome center at Washington University in St. Louis, who led the two-year effort, described online Wednesday in the journal Nature. Yet, Wilson said, the platypus genome offers an unprecedented glimpse of how evolution made its first stabs at producing mammals. It tells the tale of how early mammals learned to nurse their young, how they matched poisonous snakes at their own venomous game and how they struggled to build a system of fertilization and gestation that would eventually, through relatives that took a different tack, give rise to the first humans.
The Washington Post has a full version of the story, all about platypi and their genetic oddities.
--Tony Barboza