“This observation is consistent with recent evidence that Neanderthals consumed starch, and perhaps the domestication of fire made cooked starch available to ancient humans.” researchers say. said In a study recently published in the journal Science.
Of the eight genomes examined, multiple copies of AMY1 were found in two eastern Neanderthal genomes, one from western Neanderthals and one from Denisovans. So why did these extra copies evolve? The exact reason is still unknown, but the research team believes that the genes themselves are copy-variable, and the copy number within a population may vary from person to person. I think that means that. This mutation probably developed before humans diverged from Neanderthals and Denisovans.
with grain
For the researchers, it was inevitable that as former hunter-gatherers established agricultural societies, the number of copies of AMY1 in individual genomes would increase. Agriculture meant grains and other starch-rich foods, and the ability to regulate them meant carbohydrates.
And the data here is consistent with that. The research team “found a general trend of significantly higher AMY1 gene copy numbers in archaeologically excavated samples from the agricultural era compared to samples from the hunter-gatherer era.” stated in the same paper. study.
Before agriculture, individuals already had four to eight copies of this gene in their genomes. This variation is thought to have come from groups experimenting with food processing techniques such as grinding wild grains into flour. AMY1 copy number increased almost consistently from pre- to post-agriculture. They found that individuals from populations that were transitioning to agriculture (about 16,100 to 8,500 years ago) had about the same number of AMY1 copies as hunter-gatherers at the time.
People from 8,500 years ago who lived in more established agricultural societies showed the most copies and therefore the most evidence of adaptation to a carbohydrate-rich diet. As agriculture continues to advance, the last 4,000 years have seen the most significant increase in AMY1 copies. Modern humans have between 2 and 15 copies.
Further research could help understand how genetic variations in AMY1 copy number affect starch metabolism, including conditions such as gluten allergy and celiac disease, and overall metabolic health. there is.
Can we really blame AMY1 and amylase for carbohydrate cravings? Partially. The number of AMY1 copies in the human genome not only determines the ability to metabolize starch, but also influences the taste of starch and may confer a preference for it. Maybe we can finally stop demonizing bread.
Science, 2024. DOI: 10.1126/science.adn060
