Fast-Track Evolution Gave Rise to Deer Mouse's Pale Coat

By Allison Bond | August 31, 2009 7:00 am

deer miceThe pale-coated deer mouse that makes its home in Nebraska’s Sand Hills prairie has become a poster-mouse for evolution, based on results of a study published in Science.

The rodent typically has dark fur (bottom photo), but one Nebraska group of mice evolved to have lighter fur (top photo) after the Sand Hills formed 8,000 to 15,000 years ago. A lighter coat is advantageous because it allows the animal to blend in with its pale surroundings. But what’s more amazing is that before the formation of the Sand Hills, the deer mouse didn’t even possess the gene that controls coat color in the rodents.

The gene, which is known as Agouti, first appeared in deer mice in the Sand Hills about 4,000 years ago; after that, a mutation occurred that gave rise to the mouse’s sandy fur. “The light gene wasn’t in existence, so the mice had to “wait” until a particular mutation occurred and then selection had to act on that new mutation… It’s a two part process. First the mutation has to occur and second, selection has to increase its frequency” [BBC News], said co-author Hopi Hoekstra.

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Image: Emily Kay

MORE ABOUT: evolution, genetics
  • Jumblepudding

    Props to this species for evolving in a state where so few people thought they could.

  • Kin

    Jumblepudding, very awesome.

  • Susan

    Everything begins and ends with food. I’m sure the change of environment helps, but change of diet, especially over time, helps more.

  • Simeon

    What does change of diet help in this case? What does environment help for that matter? If diet had changed but color palette of the environment had not, this gene and subsequent mutation would have had no advantage over dark colored fur.

  • Emily Baker

    Wow i’ll try eating purple tomatoes maybe my kids will be blue.

  • DVics

    I think a few are missing the point here. You have to look at it the other way around. The change in environment didn’t help, and we don’t need to even consider food. A genetic mutation occurred, and since that mutation facilitated a change in the color of the coat, natural selecion subsequently caused the lighter colored mice to thrive, i.e. they weren’t as noticeable to predatory birds, snakes, etc.

    If this mutation never occurred, the population of darker coated mice would have eventually been reduced to nothing, and this species of mouse would not exist in this location.

  • Eman

    great evidence about the mouse


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