Smoking Gun on Evolution

Researchers at Harvard University and U.C. Berkeley have produced a study on the color differentiation observed in the deer mice that inhabit the sand dunes of Nebraska. Most of the species are gray and earthen in color (so as to blend in with their surroundings better), but the mice found on the sand dunes are much lighter (more of a tan or light brown). According to the BBC article, this difference in color is from a mutation that occurred most likely around 4,000 years ago. How do they know this, well, as the scientists put it,"most animals known to quickly evolve new features do so by expressing a variation of a gene that already exists, rather than evolving a new type of gene altogether." These dune mice evolved a new single gene that is called Agouti. Through a series of genetic tests on these mice they found that the gene did not exist prior to the time frame suggested above; furthermore, they were able to quantitatively predict the survival edge this gave the Agouti mice living on the dunes, 0.5%. To sum it up team member Professor Hopi Hoekstra puts it best when he says, "It's a two part process. First the mutation has to occur and second, selection has to increase its frequency." Pretty cool, huh!?!