Thursday, July 12, 2012
platypus from ancient genetic engineering?
October 25, 2010 10:37 AM EDT (Updated: October 25, 2010 10:43 AM EDT)views: 205 1 person recommends this comments: 7
Scientists say that the platypus genome, which was sequenced a few years ago -- the results were announced in 2008 -- shows evidence of how mammals evolved from reptiles and birds.
One interesting finding is that the male platypus chromosome (Y in mammals) is more like a bird's male chromosome (Z in birds). The female chromosome (X in mammals) is more like a bird's female chromosome (W in birds). Unlike other mammals, the playtpus male testes remain internal and never descend.
What if this really shows the results of ancient genetic engineering?
The genome of the platypus is primarily mammalian, but it also contains gene sequences of birds and reptiles.
This would explain why it is one of only two mammals that lay eggs (monotremes). The other one is the echidna, which looks like a hedgehog or a porcupine and eats ants.
Both of these strange creatures live only in Australia, in the wild. They have fur and are warm-blooded like mammals, but they are very odd in many ways. The platypus has a bill like a duck. The male platypus and the male echidna have spurs on their hind feet that can inject a toxin into their rivals and predators, causing a very painful wound. The females of both species -- like birds and unlike other mammals -- have only one orifice for both excreting waste and laying eggs. The young are underdeveloped when they hatch, and they nurse for several months. The mothers do not have nipples, so the milk pools up in little "cups" in their breast areas.
The platypus genome explains why it has characteristics of completely different kinds of animals. But how did it get that strange mix of reptile, bird and mammal genes? Did it really arise naturally? I think not.
Scientists in Australia have been working with the human genome project to sequence the genomes of their unique animals, the monotremes and the marsupials.
Marsupials, including the kangaroo, give birth to underdeveloped young that continue their gestation in the mother's pouch. The newborn marsupial attaches itself to one of the mother's nipples and doesn't let go until it is more fully developed. They are found in other parts of the world, besides Australia. For example, the opossum is native to both North and South America.
The official scientific paper is here:
The results of the opossum genome research were released in 2007.
The difference between marsupials and placental mammals appears to lie in the "junk" DNA, which was once thought to have no useful function.
The genome of the platypus has many strange features, which you can explore here: