Mice Roar Message: Genetic Change Happens Fast

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Mice Roar Message: Genetic Change Happens Fast

http://www.sciencedaily.com/releases/2007/10/071019145443.htm

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 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 UIC biological sciences professor 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 way evolution

works in an increasingly human-impacted world, " Pergams said.

Lacy studies and compares changes of Volo Bog mice both in the wild

and in subsequent generations of their offspring raised in his

laboratory.

" It was surprising to us to see how fast genetic and physical change

could occur even in the wild population, " he said.

Pergams said a lesson of the surprisingly fast replacement of the

mouse types is not to assume that animal populations are constant.

He also said there's a message for environmentalists.

" Humans are changing the global environment at unprecedented rates, "

he said. " Plants and animals react to these massive environmental

changes either by going extinct or [by] adapting very rapidly. "

Pergams and Lacy report the findings in Molecular Ecology, Volume

17, now online, and in print in late December.