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Friday, September 04, 2009

New at ARN: Dear mice: We are pleased to inform you that you are now an icon of evolution

From British physicist David Tyler, on how deer mice became the most recent icons of "evolution in action" due to coat colour variations:

What this research does not do is lend support to Charles Darwin's claim that evolution by natural selection is the key to understanding the development of biological complexity and the origin of species. the genetic changes associated with the modified coat colour are attributed to the deletion of a single amino acid in the Agouti gene - there is no increase in information and no move towards specified complexity. It is necessary to point this out because some (e.g. the BBC report) are suggesting this research is so important for evolutionary theory that it deserves iconic status.
Icon? Hard to believe, but true. Basically, losing a gene doesn't get us very far in understanding the evolution of complex life forms. What we want to know is how to gain a gene.

Anyway, I wonder whether coat colour changes lead to the formation of new species very often, in the sense that the life forms can no longer interbreed. Coat changes must usually follow local environment changes that favour one colour over another.
Animals with white winter coats may do well in a snow belt, but are highly visible otherwise. That is an example of natural selection, of course. But these changes may be short term, considering geological time, and the genes to migrate back when the environment changes may still exist. If so, it is probably a good thing because too much incidental speciation would threaten extinction any time the local environment changed.

Find out why there is an intelligent design controversy:


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