A new study published on Thursday determined that humanity’s modern-day adoration for carbs may actually predate even the emergence of the Neanderthals.
It has been assumed that the earliest humans had to indulge in a protein-heavy diet to get through the grueling days of hunting, scavenging and evading predators. However, a new study published by the journal Science debunks this long-held belief.
The study points to a specific gene that enabled humans to digest starches more easily by breaking them down into simple sugars that can be used for energy.
These genes continued to duplicate long before the rise of agriculture
Researchers at The Jackson Laboratory in Farmington, Conn., and the University of Buffalo in New York studied the genomes of 68 ancient humans. The team focused on a gene called AMY1, which allows humans to break down complex carbohydrate starches in the mouth by producing the enzyme amylase.
Almost all modern humans have multiple copies of AMY1, but how many varies from person to person. Geneticists have struggled to determine exactly how and when the gene began to expand — which ties back to when eating starches became advantageous to human health.
“The main question that we were trying to answer was, when did this duplication occur? So that’s why we started studying ancient genomes,” Feyza Yilmaz, an associate computational scientist at The Jackson Laboratory, told CNN.
“Previous studies show that there’s a correlation between AMY1 copy numbers and the amount of amylase enzyme that’s released in our saliva. We wanted to understand whether it’s an occurrence that is corresponding to the advent of agriculture. This is … a hot question.”
The researchers found that hunter-gatherers as far back as 45,000 years ago had around four to eight copies of AMY1, indicating that homo sapiens had a knack for starch even during the Mesolithic period –and before the introduction of agricultural practices.
The research also found duplication of AMY1 in the genomes of Neanderthals and the lesser-known Denisovans — an extinct hominin discovered in 2010.
The multiple copies of the gene in three separate human species indicates that it was a trait shared by a common ancestor before the lineages fractured, according to the study.
That means humans had more than one copy of AMY1 as far back as even 800,000 years ago.
The lack of a clear reason for the duplication led researchers to believe it likely happened at random.
AMY1 duplication spiked during the last 4,000 years as humans shifted away from the hunter-gatherer lifestyle toward more starch-forward diets.
The study also boosts the existing theory that carbs, not proteins, provided the extra energy necessary for the increase in human brain size over time, Taylor Hermes, an assistant professor in the department of anthropology at the University of Arkansas, told CNN.
“The authors finding that an increased copy number of the amylase gene, which results in a greater ability to break down starch, may have emerged hundreds of thousands of years before Neanderthals or Denisovans gives more credit to the idea that starches were being metabolized into simple sugars to fuel rapidly growing brain development during human evolution,” Hermes, who is unaffiliated with the study, said.
“This shows the value in continuing to mine the genomes of our human ancestors for important medical and physiological records.”
