Washington: Physical fitness matters in frogs. Those who are athletic have faster-changing genomes, say researchers, after carrying out a study of poison frogs from Central and South America.
Stretches of DNA accumulate changes over time, but the rate at which those changes build up varies considerably between species, said lead author Juan C Santos of National Evolutionary Synthesis Center in North Carolina.
For the study, the researchers scoured forests in Colombia, Ecuador, Venezuela, and Panama in search of poison frogs, subjecting nearly 500 frogs -- representing more than 50 species -- to a frog fitness test.
They had the frogs run in a rotating plastic tube resembling a hamster wheel, and measured their oxygen uptake after four minutes of exercise. The friskiest frogs had aerobic capacities five times higher than the most sluggish species, and were able to run longer before they got tired.
"Physically fit species are more efficient at extracting oxygen from each breath and delivering it to working muscles," Santos said in a release.
To estimate the rate at which each species` genome changed over time, the researchers also reconstructed poison frog family tree, using DNA sequences from fifteen frog genes.
When they estimated the number of mutations, or changes in the DNA, for each species over time, a clear pattern emerged -- athletic frogs tended to have faster-changing genomes, the `Molecular Biology and Evolution` reported.
During exercise, the circulatory system provides blood and oxygen to the tissues that are needed most -- the muscles -- at the expense of less active tissues, Santos said.