Neanderthal DNA could explain why some people are more likely to rise early, finds study

Genetics is a beautiful and complicated phenomenon. Though it can be interesting to note unintentional similarities with blood relatives, in reality, the phenomenon is very expansive. This has been proven by a recent study conducted by researchers John A. Capra, Keila Velazquez-Arcelay and Laura L. Colbran. This study shows how some humans in the present day still carry certain traits they received from their Neanderthal forefathers. It's been centuries since Neanderthals walked the earth and yet, the traits we've inherited from them are so strong that they have the power to influence the daily lives of humans through their sleeping and waking patterns. It also has a deep impact on the identities of humans, with an effect on hair color, skin tone, mental health and weight.

As per the Natural History Museum, the divergence between Neanderthals and modern humans occurred 650,000 years ago. For a long time, Homo neanderthalensis existed with Homo Sapiens in close proximity. This led to intimate encounters, which caused the genes of Neanderthals to pass into the present humans. Even to this day, some people have inherited around 2% of Neanderthal DNA into their genes from their forefathers. Keeping this in mind, researchers began to study the impact of such genes on human behavior and published them in the journal, Genome Biology and Evolution.

The findings revealed that individuals who carry genes from Neanderthals tend to be early risers. The researchers came to the common link of early rising after comparing DNA from today’s humans and DNA from Neanderthal fossils. The study shared the process in the abstract: "First, we inferred differences in circadian gene sequences, splicing and regulation between archaic hominins and modern humans. We identified 28 circadian genes containing variants with the potential to alter splicing in archaics (e.g., CLOCK, PER2, RORB and RORC) and 16 circadian genes likely divergently regulated between present-day humans and archaic hominins, including RORA. These differences suggest the potential for introgression to modify circadian gene expression."

Analysis showed that both samples had certain similar genetic variants impacting their internal body clock, known as the circadian rhythm. Speaking of the moment they came to this conclusion, John A. Capra shared with the New York Times, “That was really the most exciting moment of the study, when we saw that.”  Smithsonian Magazine in their report, revealed that the genetic material of Neandathrals gave them faster and more flexible internal body clocks. This in turn aided them in adjusting themselves to the annual daylight changes that occurred in their environment. Early Homo sapiens might have struggled with this fluctuation, but their intimate interaction with Neandathrals helped their offspring adapt better to the circumstances.

The findings do not conclude that the genes are the only reason behind the patterns of early rising. There are several other factors at play, like surroundings and society. Moreover, the DNA taken from present-day humans all came from the UK with the aid of the U.K. Biobank and hence the findings may not hold true when it comes to other countries. Therefore, the next step of action for the researchers is to expand their scope to other places. Other similarities and consequences have also been noted as a result of the genes passed on by Neandathrals. These genes had a huge overall effect on conditions like heart disease and behavior like smoking.