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Posted: Fri May 09, 2008 8:19 pm |
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| enigma |
| Deputy Dawg |
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At first dismissed as a prank, and later cited as proof that God has a sense of humour, the duck-billed platypus has finally given up its evolutionary secrets.
The creature, considered one of the strangest mammals in the world, has become the latest to have its genetic code sequenced, revealing it to be a bizarre mix of mammal, bird and reptile, with very complex sexuality. While humans have two sex chromosomes, the X and Y, the platypus has 10, with five of each kind.
An international team of scientists extracted DNA from a female platypus, named Glennie, reading all 2.2bn pairs of her genetic "letters". Thought to have begun to diverge from other mammals 170m years ago, the platypus has been regarded as the nearest thing biologists have to a missing link between the earliest reptiles and mammals. It has thick fur and produces milk for its young, yet the females lay eggs and the males produce venom - the only mammals to do so.
When first discovered in Australia in 1798, the beaver-tailed animal caused such bemusement that the zoologist George Shaw declared it could well be a hoax.
The new study, published in Nature, shows the platypus as both evolutionary relic and pioneer. Chris Ponting, at the Medical Research Council's functional genomics unit at Oxford University, said scientists had had the first chance to see if the platypus's weird appearance was reflected in its DNA: "Lo and behold, we saw genes like those in lizards and birds, as well as some like those in other mammals. It has retained many genes other mammals lost from a time when all mammals looked much like lizards."
Many of the animal's stranger characteristics are now thought to have evolved independently. The venom, which is released from the male's hind leg spurs, is thought to have developed late in the animal's history. And the remarkable electrosensitive bill, which helps the platypus hunt underwater while its eyes and ears are covered, appeared long after the platypus split from its reptilian ancestors.
The fact that the animal has five X and five Y chromosomes is "the weirdest thing about a very weird animal," said Ewan Birney, a co-author on the paper, based at the European Bioinformatics Institute, near Cambridge. "In theory it means there are 25 possible sexes, though in practice that doesn't happen."
http://www.guardian.co.uk/science/2008/may/08/genetics.wildlife |
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_________________ Sworn to Serve and Protect your ass... Not to kiss your ass. |
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Posted: Fri May 09, 2008 8:48 pm |
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| Raven |
| Google Meister |
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_________________ "The most beautiful experience we can have is the mysterious. It is the fundamental emotion that stands at the cradle of true art and true science. Whoever does not know it and can no longer wonder, no longer marvel, is as good as dead, and his eyes are dimmed." |
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Posted: Fri May 09, 2008 9:18 pm |
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| Anonymouse |
| Living impaired |
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| Can we kick it out of the mammal club already? |
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Posted: Sat May 10, 2008 12:22 am |
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| Yaish |
| Intel Chief |
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| Joined: 14 Oct 2005 |
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| Anonymouse wrote: | | Can we kick it out of the mammal club already? |
Well we gave them their own table in the lunchroom at least. Them and echidnas. |
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_________________ ... the kilt had concealed a blaster strapped to one thigh and a knife to the other. He was aware of the present gentle customs against personal weapons, but he felt naked without them. Such customs were nonsense anyhow, foolishment from old women - there was no such thing as "dangerous weapons," only dangerous people.
--Robert Heinlein in Methuselah's Children |
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Posted: Sat May 10, 2008 12:45 am |
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| Raven |
| Google Meister |
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| Location: Detroit, MI, USA, North America, Earth, Sol, Orian's Arm, Milkyway, Uni Alpha-Prime |
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| can we do something about marsupials too... they freak me out just as much... |
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_________________ "The most beautiful experience we can have is the mysterious. It is the fundamental emotion that stands at the cradle of true art and true science. Whoever does not know it and can no longer wonder, no longer marvel, is as good as dead, and his eyes are dimmed." |
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Posted: Sat May 10, 2008 1:03 am |
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| Yaish |
| Intel Chief |
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| Joined: 14 Oct 2005 |
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| Well we stuck all those down in Australia too, except for those sneaky opossums. Someone thought they were just ugly rats and let them stay. |
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_________________ ... the kilt had concealed a blaster strapped to one thigh and a knife to the other. He was aware of the present gentle customs against personal weapons, but he felt naked without them. Such customs were nonsense anyhow, foolishment from old women - there was no such thing as "dangerous weapons," only dangerous people.
--Robert Heinlein in Methuselah's Children |
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Posted: Sat May 10, 2008 9:27 am |
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| Anonymouse |
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| Marsupials can't help they're a little retarded. |
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