Humans’ fascination with carbs runs deeper than we thought: The genes that provide instructions for enzymes that digest starch date back more than 800,000 years, predating the development of agriculture and perhaps even the split between Homo sapiens and Neanderthals. This is the finding from the Jackson Laboratory of Genomic Medicine and the University of Buffalo, and is published in the journal Science.
Neanderthal and Denisovan genomes discovered
The team found that hunter-gatherers around 45,000 years ago had an average of four to eight copies of AMY1, suggesting that Homo sapiens enjoyed starchy foods long before the introduction of human-like crops. But research has gone a step further, showing that competition for the AMY1 gene is present even in the genomes of Neanderthals and Denisovans, extinct hominids first discovered in 2010. The property comes from a common ancestor before humans split from our cousins. This means that ancient humans had multiple copies of AMY1 800,000 years ago.
Genealogy
It’s not clear when AMY1 first matched up, but it seems to have been random. The presence of multiple copies likely leads to genetic effects that make people more efficient at adapting to new foods when they encounter different environments, especially those rich in flour and rice grains.
Carbohydrates and brain size
The analysis also showed that the number of AMY1 copies found in humans has increased significantly over the past 4,000 years, likely due to natural selection as humans transitioned from a hunting lifestyle to farming and ranching.
The latest research supports a new theory that the energy needed to grow the human brain over time comes from carbohydrates, not proteins.
