Mice roar message: genetic change ha...( While looks can be deceiving heredit...)

While looks can be deceiving, heredity is revealing, and two scientists who've studied the genetic makeup of a common field mouse report that what's most revealing to them is how fast both genes and morphology can change.

Oliver Pergams, visiting research assistant professor of biological sciences at the University of Illinois at Chicago, and Robert Lacy, population geneticist and conservation biologist at the Chicago Zoological Society, compared the genetic makeup of 115 white-footed mice in the Volo Bog State Natural Area northwest of Chicago using mitochondrial DNA taken from collection samples as old as 150 years and mice collected in recent years.

They found a new type of mouse replaced the old type in Volo Bog between 1976 and 2001.

"The new mice were genetically very different," says Pergams. Structural changes were readily apparent. "Looking at size and shape, the new mice were much bigger and a little flatter."

Pergams and Lacy report the findings in Molecular Ecology, Volume 17, now online, and in print in late December.

Pergams and UIC biological sciences professor Mary Ashley reported in 2001 on similar morphological changes in size and shape over the past century of two widely disparate habitats and species -- deer mice on three different California Channel Islands, and black rats from two Galapagos Islands. While Pergams found these coincidental changes surprising, he said it is too soon to say if this is somehow related to world climate change.

Pergams said the Volo Bog change is best explained by the old mice being replaced by new mice migrating from distinct neighboring populations that are better adapted to survival in the protected bog, which is now surrounded by suburban residential communities.

"This was likely helped by the large environmental changes occurring over the 1976-2001 time period. Replacement with better-adapted genotypes from external populations may be a common wa
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