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Secrets of the platypus revealed
Scientists seeking to solve the riddle of the platypus have proved it is the first animal to have evolved from reptile to mammal and has the characteristics of both.
One of the oddest creatures in nature, the semi-aquatic platypus is an egg-laying mammal which produces milk and has fur, has a bill like a duck and venom like a snake, flowing from a spur under its hind feet.
It is so strange that when the first stuffed specimens arrived in Europe at the end of the 18th century, biologists believed they were looking at a taxidermist's hoax, a composite stitched together from the body of a beaver and the snout of a giant duck.
But now, in what is considered a milestone for Australian genetics, an international team of 100 researchers, including 26 from Australia, have mapped out the full set of chromosomes of the platypus.
It helps explain the platypus' odd mix of body features.
In an article published in Nature magazine today, the authors write: "The mixture of reptilian, mammalian and unique characteristics of the platypus genome (full set of chromosomes) provides many clues to the function and evolution of all mammalian genomes."
The findings will provide the critical background to inspire advances in other investigations of mammalian biology and evolution, the article says.
"The platypus genome is extremely important, because it is the missing link in our understanding of how we and other mammals first evolved," explained Oxford University's Chris Ponting, one of the study's architects.
"This is our ticket back in time to when all mammals laid eggs while suckling their young on milk."
Kathy Belov, from the faculty of veterinary science at the University of Sydney, said the study had proved that the platypus was the first species to diverge from reptile to mammal.
Her specific interest is in the immune system.
"What we've found is really interesting, because the platypus is born without an immune system at all, unlike humans," Dr Belov told AAP.
"So we went looking for molecules that would produce immunity. What we found is molecules that develop into their own microbials (broad spectrum antibiotics).
"This is big news for science."
Dr Belov said researchers and scientists now hope to use the microbials to develop antibiotics that fight super bugs.
"These will be more effective than anything we've got. It's kind of cool that from something like this we can end up developing therapeutics."
Researchers also found the venom genes, found only in male platypuses, are similar to that of snakes and reptiles.
"But basically we've shown they evolved independently. This is a big deal for us," Dr Belov said.
"We found the venom genes, but we do not know what they do. We presume they will cause pain but we find if you come to understand what they do and how they will produce pain, then we can develop novel methods of pain relief."
Other areas studied include the sex chromosomes.
It was discovered that male platypuses have five "x" genes and five "y" genes, while females have 10 "x" genes.
Humans have two sex chromosomes.
"It's really weird. We still don't know how platypus determine sex. The gene that does it in other mammals doesn't do it in platypus."
The study is part of a larger study of how mammals developed, by the US-based National Human Genome Research Institute.
"We've probably learnt more during this study about platypuses than we have in decades and decades," Dr Belov said.
Native to eastern Australia and Tasmania, the platypus is thought to have split off from a common ancestor shared with humans approximately 170 million years ago.
One of the oddest creatures in nature, the semi-aquatic platypus is an egg-laying mammal which produces milk and has fur, has a bill like a duck and venom like a snake, flowing from a spur under its hind feet.
It is so strange that when the first stuffed specimens arrived in Europe at the end of the 18th century, biologists believed they were looking at a taxidermist's hoax, a composite stitched together from the body of a beaver and the snout of a giant duck.
But now, in what is considered a milestone for Australian genetics, an international team of 100 researchers, including 26 from Australia, have mapped out the full set of chromosomes of the platypus.
It helps explain the platypus' odd mix of body features.
In an article published in Nature magazine today, the authors write: "The mixture of reptilian, mammalian and unique characteristics of the platypus genome (full set of chromosomes) provides many clues to the function and evolution of all mammalian genomes."
The findings will provide the critical background to inspire advances in other investigations of mammalian biology and evolution, the article says.
"The platypus genome is extremely important, because it is the missing link in our understanding of how we and other mammals first evolved," explained Oxford University's Chris Ponting, one of the study's architects.
"This is our ticket back in time to when all mammals laid eggs while suckling their young on milk."
Kathy Belov, from the faculty of veterinary science at the University of Sydney, said the study had proved that the platypus was the first species to diverge from reptile to mammal.
Her specific interest is in the immune system.
"What we've found is really interesting, because the platypus is born without an immune system at all, unlike humans," Dr Belov told AAP.
"So we went looking for molecules that would produce immunity. What we found is molecules that develop into their own microbials (broad spectrum antibiotics).
"This is big news for science."
Dr Belov said researchers and scientists now hope to use the microbials to develop antibiotics that fight super bugs.
"These will be more effective than anything we've got. It's kind of cool that from something like this we can end up developing therapeutics."
Researchers also found the venom genes, found only in male platypuses, are similar to that of snakes and reptiles.
"But basically we've shown they evolved independently. This is a big deal for us," Dr Belov said.
"We found the venom genes, but we do not know what they do. We presume they will cause pain but we find if you come to understand what they do and how they will produce pain, then we can develop novel methods of pain relief."
Other areas studied include the sex chromosomes.
It was discovered that male platypuses have five "x" genes and five "y" genes, while females have 10 "x" genes.
Humans have two sex chromosomes.
"It's really weird. We still don't know how platypus determine sex. The gene that does it in other mammals doesn't do it in platypus."
The study is part of a larger study of how mammals developed, by the US-based National Human Genome Research Institute.
"We've probably learnt more during this study about platypuses than we have in decades and decades," Dr Belov said.
Native to eastern Australia and Tasmania, the platypus is thought to have split off from a common ancestor shared with humans approximately 170 million years ago.
