If you’ve ever found it challenging to cut back on carbs, ancient DNA might hold the key to your struggles. Recent research indicates that humans carry multiple copies of a gene essential for breaking down complex carbohydrates, particularly starches found in foods like bread and pasta.
This gene, known as the salivary amylase gene (AMY1), plays a significant role in our ability to digest starchy foods, and a new study sheds light on its fascinating evolution.
Led by researchers from The University of Buffalo (UB) and The Jackson Laboratory (JAX), the study reveals that early duplications of the AMY1 gene may have occurred over 800,000 years ago-well before the advent of agriculture. This genetic development laid the groundwork for the significant variations we see in human populations today, influencing how effectively individuals can digest starch.
Unpacking the AMY1 Gene
“The more amylase genes you have, the more amylase you can produce, enhancing your ability to digest starch,” explained Dr. Omer Gokcumen, a professor in UB’s Department of Biological Sciences and the study’s corresponding author.
Using groundbreaking techniques like optical genome mapping and long-read sequencing, Gokcumen and his team were able to map the AMY1 gene region with unprecedented accuracy. Unlike traditional short-read sequencing methods, which often struggle to distinguish between nearly identical gene copies, long-read sequencing provided a clearer view of the evolutionary path of AMY1 duplications.
Legacy of Adaptation
The research team analyzed the genomes of 68 ancient humans, including a 45,000-year-old specimen from Siberia, revealing that pre-agricultural hunter-gatherers already possessed an average of four to eight copies of the AMY1 gene. This finding indicates that humans were well-equipped to metabolize starch long before they began domesticating plants.
Moreover, the study found that both Neanderthals and Denisovans also had multiple AMY1 copies, suggesting that these gene duplications may have occurred more than 800,000 years ago, significantly earlier than previously thought.
The research also emphasizes the influence of agriculture on AMY1 variation. While early hunter-gatherers had a broad range of gene copies, the average number of AMY1 copies among European farmers surged over the past 4,000 years, likely due to their starch-heavy diets.
“Individuals with higher AMY1 copy numbers likely digested starch more efficiently, resulting in greater reproductive success. This led to the propagation of AMY1 copy numbers over time,” Gokcumen noted.
Implications for Future Research
These findings align with a recent study from the University of California, Berkeley, which reported an increase in the average number of AMY1 copies among Europeans from four to seven over the last 12,000 years.
Future research promises to uncover the precise effects of AMY1 variations, offering vital insights into genetics, nutrition, and overall health. As we continue to unravel our genetic history, the ancient DNA that has shaped our dietary adaptations may finally provide the answers we seek in our quest for better health and well-being.