Do Neanderthal Genes Influence Our Circadian Rhythms?

Thursday - December 14 2023, 16:28 UTC - 11 months ago

A new study published in the journal Genome Biology and Evolution has revealed that some genetic variants from Neanderthals may have influenced the circadian rhythms of modern humans. The researchers examined the differences in the circadian genes, using artificial intelligence methods to identify variants with altered gene expression between Neanderthals and modern humans. Data from the UK Biobank provided evidence that these variants allowed people with higher Neanderthal ancestry to better adjust their circadian clocks to the seasonal shifts in the environment.

Suppose you are one of those people who love to wake up early and go to bed early. In that case, you may have inherited this trait from your Neanderthal ancestors, according to a new study published in the journal Genome Biology and Evolution.The study, conducted by researchers from Oxford University Press, reveals that some genetic variants from Neanderthals may have influenced the circadian rhythms of modern humans, making them more adapted to the high-latitude environments of Eurasia .

Neanderthals and DenisovansThe origin of all anatomically modern humans can be traced back to Africa, around 300 thousand years ago. In Africa, many of their biological features were shaped by environmental factors.Later, about seventy thousand years ago, the ancestors of modern Eurasian humans migrated out to Eurasia, where they were exposed to new and diverse environments, including higher latitudes with greater seasonal variation in daylight and temperature .

However, other hominins such as Neanderthals and Denisovans had already been living in Eurasia for over 400,000 years. These archaic hominins diverged from modern humans around 700,000 years ago, and as a consequence, our ancestors and archaic hominins evolved under different environmental conditions.This led to the accumulation of genetic variation and phenotypes that were specific to each lineage .

Later, when humans migrated to Eurasia, they interbred with the archaic hominins present on the continent, which created the possibility for humans to acquire genetic variants that were already adapted to the new environmentsEarlier studiesWhile earlier studies have shown that much of the archaic hominin ancestry in modern humans was not advantageous and eradicated by natural selection, some of these variants that remain in human populations demonstrate evidence of adaptation .

For instance, archaic genetic variants have been linked to variations in hemoglobin levels at higher altitudes in Tibetans, immune resistance to novel pathogens, levels of skin pigmentation, and fat composition.Alterations in the pattern and degree of light exposure have biological and behavioral implications that can lead to evolutionary adaptations. Insects, plants, and fishes have been extensively studied to explore the evolution of circadian adaptation, but this area remains understudied in humans .

Studying the circadian genesThe researchers examined the differences in the circadian genes, which regulate the body"s internal clock and respond to changes in light and temperature. They identified 246 circadian genes and found hundreds of genetic variants specific to each lineage.They also used artificial intelligence methods to pinpoint 28 circadian genes with variants that could alter gene expression in archaic hominins and 16 circadian genes likely regulated differently between modern and archaic humans .

This suggested that the circadian clocks of Neanderthals and modern humans were not the same.To test the effects of these genetic variants, the researchers analyzed data from the UK Biobank, a large health and genetic information database from half a million people.Adjustin for seasonThey found that people with higher Neanderthal ancestry had different patterns of gene expression in clock genes at different latitudes .

These variants allowed them to better adjust their circadian clocks to the seasonal shifts in the environment, which could have been beneficial for human populations living farther north.Overall, the study demonstrates that variants acquired from archaic hominins can contribute to circadian adaptation in modern humans.