GOOD MORNING, CAVEMEN!

‘Early riser’ DNA

The early cave dweller gets the worm.

People prone to early rising could have the Neanderthals to thank as a new study suggests that ancient genetic mutations could be responsible for modernday sleep cycles.

A team of researchers from various US universities found that DNA passed down from two ancestral groups of modern-day humans — Neanderthals and Denisovans — may have been the progenitors of the morning-person gene.

“This was really exciting to us, and not expected,” Tony Capra, a professor and co-director of the Biological and Medical Informatics program at the University of California, San Francisco, told New Scientist.

“Neanderthals and Denisovans passed on DNA that increased our morningness, and this has been retained in modern human populations.”

Past research has linked present-day biological benefits — fertility and immunity, for instance — to the genes of Neanderthals and Denisovans.

In the recent study, published Thursday in Genome Biology and Evolution, researchers wondered if our circadian rhythms evolved from our distant ancestors in the same way.

Researchers noticed the genes that became more common over time were connected to the body’s circadian clock, the 24-hour cycle that dictates the behavioral, mental and physical changes internally, The New York Times reported.

The scientists compared the genomes of three Neanderthals and one Denisovan to that of thousands of present-day humans, specifically highlighting the 246 genes responsible for regulating the circadian clock. Overall, they found more than 1,000 unique genetic mutations throughout the sample groups, identifying those that were specific to modern-day humans or our ancestors.