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Walking Before Flying
An anonymous reader writes "BYU biostaticians report in Nature their genetic analysis of the insect, known as the 'walking stick', which apparently gives a contrapuntal example of reversible evolution. Called Dollo's Law, the principle holds that the same evolutionary pathway can never be backtracked, because of random mutations. But this insect class first had wings, lost them, then got them back again. So what's next for some humans: a happy return to dragging their knuckles?"
That was part of one of the articles I read about this: They said that the same genes control whether wings or legs are well-formed, so when the wing is switched off, the genes in it are still protected from too much mutation until the wings are switched on again.
9 93269.
Then again, I'm by far no expert on the subject...
Here it is: http://www.newscientist.com/news/news.jsp?id=ns99
Researchers assumed wings could not come back once lost as the genes needed to create them would mutate beyond repair once the wings disappeared. But Whiting says there is evidence from the fruit fly Drosophila that the same genes contain instructions for forming wings and legs.
If the same were true for stick insects, there would be an evolutionary pressure to stop wing genes from mutating, even in the insects that did not have wings. Those genes could then be turned back on in the future.
Daniel
Carpe Diem
However, if mutations are truly random, isn't it necessary that they at least have the possibility to recreate a lost pathway, no matter how complex?
I believe it was more a prediction that if evolution operates as we expect, organisms would be unlikely to 'solve' an evolutionary problem the same way twice. It was not so much saying such an occurrance was impossible, but that it's occurance would out of keeping with the idea of evolution being pushed by random mutations.
That said, Dollo died in 1931, so modern discoveries like pretty much all DNA/genetic evidence wasn't available to him. I'm not sure here, but I don't think a lot of weight was put in Dollo's law anymore. Anyone out there know of reasons someone would even bother mentioning that their research contradicted Dollo's law?