Some mouse research produces results far past the lives of the individual mice.
Patrick Carter, a biologist who studies evolution at Washington State University, has been using generations and generations of data from previous studies to analyze the way the mice evolve.
In particular, Carter has been crunching the numbers for how much mice will get in their wheels and run – and how that affects later generations. He began this work as a post-doctoral fellow at the University of Wisconsin years ago and has recently been studying what’s happened to that colony since.
Carter, who is interested in the ways that complex traits evolve, wanted to see how the wheel-running affected other aspects of the mice’s lives. In the initial study, two groups of mice were created. In one group, mice that ran the most on the wheel voluntarily were selected to breed. In the other, breeding was at random.
Carter wanted to see how traits evolved together in the mice. For example, generations of mice that run more begin to evolve the ability to take in more oxygen. When traits correspond like that, they can speed up evolution. But other traits may evolve as well – such as joint problems – and they may be less conducive to rapid evolution, he said.
“I’m very interested in the constraints on evolution,” Carter said. “It influences the tempo of evolution.”
What he found was that the runners improved at a surprising rate. By the sixth generation – mice can produce several generations a year – the mice were running much more than the first generation. By the 16th, they were running more than three times as much. Some of the mice were running up to 15 miles a day.