May 10 (UPI) -- Scientists have discovered a gene in fruit flies that helps the insect fight the urge to take an afternoon siesta.
Naps can sometimes be beneficial. Animals programmed to nap can avoid expending energy during the hottest part of the day. For humans, naps can help boost memory and learning.
But for every nap, there is an opportunity cost. Time spent napping might be better spent searching for food or mates.
While analyzing the genome of the fruit fly, scientists discovered a gene that is activated when temperatures are cooler. The "daywake" gene suppresses the fly's urge to take an afternoon nap.
"This gene contributes to behavioral flexibility, or the ability to hide from the noontime sun when weather is hot but engage in activities good for survival when the weather is cool," Isaac Edery, a professor at Rutgers' Center for Advanced Biotechnology and Medicine, said in a news release. "That probably helped these flies expand beyond their ancestral home in equatorial Africa to successfully colonize temperate zones around the world."
On the fruit fly's genome, the daywake gene neighbors the "period" gene, which dictates the insect's circadian rhythms. The period gene helps fruit flies maintain proper wake-sleep cycles. A portion of the DNA sequencing inside the period gene encourages daywake gene activity. The link between the two genes operates more efficiently when fruit flies are exposed to cold temperatures.
Scientists have never before observed interaction between overlapping gene sequences, a novel genetic mechanism that could help scientists uncover other types of gene expression strategies.
"Although the daywake gene is not present in humans, our finding reinforces the idea that nighttime sleep and daytime siesta are governed by distinct mechanisms and serve separate functions for health and survival," Edery said.
Researchers described their discovery of the daywake gene this week in the journal Current Biology.