Reason humans love to eat bread and pasta could be down to ancient DNA, study claims

A new study has suggested that the ability to start digesting starchy foods in the mouth may have developed before the split from Neanderthals and before humans even began farming

Your fondness for carbohydrates such as bread and pasta could be due to ancient DNA, new research suggests. The study indicates that humans may have developed the ability to begin digesting these foods in the mouth long before they began farming, possibly even prior to the divergence from Neanderthals.

The research found that the gene for starch-digesting saliva may have first duplicated over 800,000 years ago, laying the groundwork for the genetic change that influences our diets today. Duplication is a type of mutation that results in one or more copies of a gene.

It has been known for some time that humans carry multiple copies of a gene that allows the starch in complex carbohydrates – including foods like potatoes, rice and certain fruits and vegetables – to start breaking down in the mouth. This is the initial step in digesting these foods, and the more copies of these genes people have, the better they are at breaking down carbohydrates.

However, it's been difficult for researchers to determine when and how the number of these genes increased. A new study led by the University of Buffalo (UB) and the Jackson Laboratory (JAX) in the US discovered that the duplication of the gene – known as the salivary amylase gene (AMY1) – may not only have helped shape human adaptation to starchy foods, but may have occurred as far back as over 800,000 years ago, long before the advent of farming.

The enzyme amylase is not just crucial for converting starch into glucose—it's also a key contributor to bread's delicious taste. UB College of Arts and Sciences' trailblazing scientist, Omer Gokcumen, stated: "The idea is that the more amylase genes you have, the more amylase you can produce and the more starch you can digest effectively.", reports the Mirror.

Research involving the analysis of genomes from 68 ancient humans, including a venerable specimen from Siberia dated at 45,000 years old, found that hunter-gatherers who pre-dated farming had multiple copies of a gene linked to starch digestion. This discovery suggests that those with a wider array of these genes were widespread across Eurasia prior to the domestication of plants and the subsequent rise in starch intake.

Furthermore, duplications of the AMY1 gene were observed in both Neanderthals and Denisovans, indicating that such genetic changes may have first occurred over 800,000 years ago. This timeline precedes the split of modern humans from Neanderthals by a significant margin.

Kwondo Kim, a lead author of the study, noted: "This suggests that the AMY1 gene may have first duplicated more than 800,000 years ago, well before humans split from Neanderthals and much further back than previously thought."

Consequently, the research posits that early duplications of the AMY1 gene laid the groundwork for genetic variability surrounding amylase. This genetic diversity provided early human populations with the means to adapt their diets in line with technological advancements and changes in their lifestyle, which increasingly involved starch consumption.

The research, published in the Science journal, indicates that while early hunter-gatherers had multiple gene copies, European farmers saw an increase in the average number of AMY1 copies over the past 4,000 years, likely due to their starch-rich diets. The study used genome mapping and sequencing to detail the AMY1 gene region.