Adaptation found in mouse genes

LINCOLN — The little deer mouse provides big answers about how evolution works, according to findings by a University of Nebraska-Lincoln researcher to be published this month.

Jay Storz, an assistant professor of evolutionary biology, compared the genes of deer mice that live in lowland prairies with those that live in the mountains. He identified mutations in four different genes that enable the high-country mice to survive in the thin air of high altitudes.

“This is significant to our understanding of how Darwinian evolution works,” he said. “There have been very few cases where it's been possible to identify a specific mechanism for adaptation.”

Storz worked with other UNL scientists as well as researchers from the University of Kansas, the University of Porto in Portugal and the University of Aarhus in Denmark in his study, supported by grants from the National Institutes of Health and the National Science Foundation.

The wild mice were captured in Colorado: 38 lowland mice from Yuma County, near the Kansas border; and 37 highland mice from the peak of Mount Evans, west of Denver.

The researchers found that although the two mice breeds are physiologically different, their genes are virtually identical — except for those that govern the oxygen-carrying capacity of their hemoglobin.

There is less oxygen available at higher altitudes, and the genetic difference enables highlands mice to make more efficient use of oxygen, Storz and his fellow researchers concluded. The mechanism is similar to an adaptation found in humans, in which the hemoglobin of fetuses in utero has a higher oxygen-binding capacity to compensate for the low-oxygen intrauterine environment.

The research demonstrates how natural selection causes organisms to adapt to specific surroundings, Storz said. He said future research with deer mice holds more promise for a greater understanding of evolution.

“This particular species is the most widely distributed, most abundant mammalian species in North America,” he said. “They've adapted to a really wide range of environmental conditions, and they exhibit a lot of geographical variation. It makes them a fascinating study animal.”

Storz's article will be published in the Aug. 10-14 online edition of the Proceedings of the National Academy of Science and will appear in the printed journal later in the month.

Contact the writer:

402-473-9581, leslie.reed@owh.com

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