A long-held theory of the development of limbs is overturned by a study that shows the molecular wherewithal to make hands and feet was present long before the first fish took the momentous step on to land.
Animals with limbs - tetrapods - first came onto the scene about 365 million years ago. However, fish already possessed the pattern of gene activity associated with helping to grow hands and feet which was present in them at least 400 million years ago, according to research at the University of Chicago.
“We found that the genetic capability seen in tetrapods to build limbs is present in even more primitive fish,” said lead author Marcus Davis, a postdoctoral fellow in Prof Neil Shubin’s lab at the University of Chicago.
This suggests a very interesting thought. The traditional theory of evolution by mutation filtered by natural selection implies that genetic variations take hold in populations in response to selection pressures, where the mutations accord individuals with advantages in survival and/or reproduction. Why would fish need a genetic predisposition to form legs and feet if they had no environmental selection pressure to do so?
Well...
... what if an Intelligent Designer decided to "salt in" some interesting genes -- you know, to sort of guide the path of evolution in a particular direction?
Not sayin' it was Jehovah, or the Flying Spaghetti Monster, or any particular deity or entity. I'm just sayin', is all.
Care to comment, Mr Dawkins?
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