Early bird tendencies may come from our Neanderthal ancestors, a new genome study reveals
3:21 PM EST, December 15, 2023
The studies imply that the inherent tendency of some individuals to go to bed and rise early could stem from genetic inheritance from Neanderthals.
The early bird habits of Neanderthals
The story unfolds around 300 thousand years ago when anatomically modern humans started emerging from Africa. Approximately 70 thousand years back, a fraction of the human population began migrating from Africa to Eurasia. Here they encountered varied environmental conditions, including seasonal disparities in day length and temperature.
In Eurasia, since about 400 thousand years ago, our relatives like the Neanderthals and Denisovans have been residing. We evolved and diverged from them roughly 700 thousand years ago. During this 400-thousand-year period, these relatives developed various adaptations to survive colder climates.
When migrants from Africa met their relatives, the Neanderthals and Denisovans again around 70 thousand years ago, interbreeding and gene exchange began.
Researchers analyzed 246 genes associated with the human circadian rhythm. Using artificial intelligence, they were able to pinpoint several dozens that could have evolved due to crossbreeding with archaic human species.
Subsequently, these scientists juxtaposed the results of their research with data from the UK Biobank, allowing them to trace the sleep-wake habits of several hundred thousand people in relation to their circadian rhythm. According to their findings, individuals with these gene variants showed a marked inclination towards rising early and retiring early as well.
John A. Capra from the University of California in San Francisco (USA), the lead author of the study, explains: "By associating archaic DNA, comprehensive genetic studies in contemporary people, and artificial intelligence, we have unearthed significant genetic differences in the circadian rhythm of Neanderthals and modern humans."
Capra further elucidates that analysis of Neanderthal DNA in the human genome revealed that this archaic DNA influences the circadian rhythms of modern humans, inclining them towards rising early.
