London - Laziness may be written into our DNA, say scientists.
Genetic traits may predispose some people to being less motivated for physical hard work, a study suggested.
Researchers were able to selectively breed rats that were either extremely active or extremely lazy and they say this indicates that genetics play a role in our willingness to exercise.
Co-author Professor Frank Booth, of Missouri University, said: “We have shown it is possible to be genetically predisposed to being lazy.
“This could be an important step in identifying additional causes for obesity in humans.
“It would be very useful to know if a person is genetically predisposed to having a lack of motivation to exercise, because that could potentially make them more likely to grow obese.”
The study, published in the American Journal of Physiology, measured how many times each rat voluntarily went on a running wheel during a period of six days.
The top 26 runners were then bred with each other and the same process was applied to the 26 laziest rats.
After the breeding programme had been repeated for ten generations, the line of active rats ran ten times more than the line of lazy rats.
The researchers studied the levels of mitochondria in the rats’ muscle cells, compared body composition and conducted genetic evaluations.
Co-author Dr Michael Roberts said: “While we found minor differences in the body composition and levels of mitochondria in muscle cells of the rats, the most important thing we identified were the genetic differences between the two lines.
“Out of more than 17 000 different genes in one part of the brain, we identified 36 genes that may play a role in predisposition to physical activity motivation.”
The researchers now plan to explore the effects of the identified genes on humans’ willingness to exercise. - Daily Mail