We probably owe the chronotype of “early birds” to mixing Homo sapiens with Neanderthals

When the first humans of our species arrived in Europe (and also in Asia) at the end of the youngest ice age A wise man, they entered an environment that was very different from their African homeland. They had to adapt to a whole host of new environmental factors, including much greater variability in day length throughout the year. In Africa, days and nights are more or less the same length throughout the year. In Europe, the people of the species A wise man they encountered very long summer days followed by very long nights in winter.

Kudos to cross-species tangles

Fortunately, at that time, our very close relatives, the Neanderthals, who were better adapted to life at higher latitudes, had been living in Europe for quite some time. Our ancestors occasionally interbred with them, and thanks to these interbreedings, we have a number of Neanderthal sequences in our genome.

A team of American experts who led John Capra from the University of California, San Francisco, analyzed selected human genomes using special artificial intelligence, equipped with algorithms that allow it to work with DNA sequences. During this analysis, the artificial intelligence looked for archaic gene variants that are responsible for our internal biological rhythms.

Our body has a sophisticated biological clock system that controls a number of internal processes, from digestion to memory storage, while also being set to allow us to respond to a variety of environmental conditions, including the length of day and night. Researchers have managed to track down a number of gene variants related to internal clocks, which we seem to have acquired thanks to the aforementioned mess with Neanderthals.

Neanderthal morning birds

Detailed analysis of these variants, which so far were not published and thus did not pass the peer review process, led scientists to the conclusion that most of the changes associated with the acquisition of “Neanderthal” sequences associated with the internal clock are in one direction – they significantly increase the probability that their bearer will be a so-called “morning bird.”

TIP: “Morning birds” are healthier and perform better at work

It is not yet completely clear how early rising is involved in adaptation to higher latitudes. In any case, it cannot be overlooked that a number of other species that live in these areas today show the same shifts in their internal clocks. For example, in fruit flies, early bird genes help synchronize their internal biological clocks with the summer season, when the days are longer.