Garland's Long-term Experiment With Laboratory House Mice
In 1993, Theodore Garland, Jr. and colleagues started a long-term experiment that involves selective breeding for high voluntary activity levels on running wheels. This experiment also continues to this day (> 50 generations). Mice from the four replicate "High Runner" lines evolved to run 3 times as many running-wheel revolutions per day as compared with the four unselected control mice groups, mainly by running faster than the control mice rather than running for more minutes/day.
The HR mice exhibit an elevated maximal aerobic capacity when tested on a motorized treadmill and a variety of other traits that appear to be adaptations that facilitate high levels of sustained endurance running (e.g., larger hearts, more symmetrical hindlimb bones). They also exhibit alterations in motivation and the reward system of the brain. Pharmacological studies point to alterations in dopamine function and the endocannabinoid system. The High Runner lines have been proposed as a model to study human attention-deficit hyperactivity disorder (ADHD), and administration of Ritalin reduces their wheel running approximately to the levels of Control mice. Click here for a mouse wheel running video.
Read more about this topic: Experimental Evolution
Famous quotes containing the words garland, long-term, experiment, laboratory, house and/or mice:
“Hear, my child, your father’s instruction, and do not reject your mother’s teaching; for they are a fair garland for your head, and pendants for your neck.”
—Bible: Hebrew, Proverbs 1:8-9.
“The strongest and most effective [force] in guaranteeing the long-term maintenance of ... power is not violence in all the forms deployed by the dominant to control the dominated, but consent in all the forms in which the dominated acquiesce in their own domination.”
—Maurice Godelier (b. 1934)
“Life is short, the art long, opportunity fleeting, experiment treacherous, judgment difficult.”
—Hippocrates (c. 460–370 B.C.)
“With all of its bad influences, T.V. is not to be feared.... It can be a fairly safe laboratory for confronting, seeing through, and thus being immunized against unhealthy values so as to be “in the world but not of it.””
—Polly Berrien Berends (20th century)
“A man’s worst enemies are those
Of his own house & family;
And he who makes his law a curse,
By his own law shall surely die.”
—William Blake (1757–1827)
“Dragons beget dragons, and phoenixes, phoenixes; and the offspring of mice will know how to chew holes.”
—Chinese proverb.