Carbohydrates take up a major spot in daily diet. Though many modern fitness goals begin with limiting carb intake, ancient DNA shows it is only natural for us to love carbohydrates.
We have already figured out that humans carry many copies of a gene that aids in breaking down carbohydrates right from the moment we chew the food down. Starchy foods like bread and pasta become sweeter the longer they stay in the mouth; kudos to the enzyme amylase that breaks down starch into simpler carbohydrates. However, scientists weren’t sure about when and how the number of these genes expanded.
Now, a new study undertaken by the University of Buffalo and the Jackson Laboratory have shed some light on when and how this gene, called the salivary amylase gene or AMY1, expanded.
According to their study, AMY1 helped humans adapt to a carb-based diet 800,000 years ago. To put into perspective, our love for carbs predates agriculture.
How long have we been loving carbs?
After analyzing the genomes of 68 human beings of the prehistoric era, scientists have found that prehistoric hunter-gatherer humans had four to eight copies of the AMY1 gene. This proves that ancient hunter-gatherer humans had a fair amount of the salivary amylase gene long before humans started practicing agriculture.
The study also discovered that duplication of this gene occurred in Neanderthals and Denisovans, further back than first thought and much before humans split from Neanderthals.
According to the paper’s corresponding author, Gokcumen, duplications in our genome laid the groundwork for a shift to a starch-based diet with the development of technology and lifestyle.
How agriculture impacted AMY1 variation?
Although early hunter-gatherers had multiple copies of the AMY1 gene, European farmers saw a sharp rise in the average number of AMY1 copies over the past 4000 years, owing to the shift to a starch-rich diet.
According to Gokcumen, lineages with higher AMY1 copy numbers were digesting more starch and having offspring. Over the evolutionary timeframe, these lineages with more AMY1 thrived better. Adding substance to this thought is a paper published by the University of California, Berkeley, in Nature, which found that humans in Europe expanded their average number of salivary amylase genes from four to seven in just a period of 12,000 years.
So the next time you feel that you are high on carbs, cut yourself some slack and blame evolutionary genetics at play.
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