Ancient DNA May Explain Our Love for Carbs, Study Finds

A new study co-led by researchers from the University at Buffalo (UB) and the Jackson Laboratory (JAX) sheds light on how ancient duplications of a gene that helps digest starch may have played a key role in human evolution. The gene, known as the #salivary amylase gene (#AMY1), produces the #enzyme amylase, which begins breaking down starchy foods like bread and pasta in the mouth. The research suggests that the duplication of this gene first occurred over 800,000 years ago, long before the advent of farming, and helped early humans adapt to starch-rich diets.

Historically, it has been difficult to pinpoint when this gene expanded in humans due to its near-identical copies. However, the team used advanced techniques, such as optical genome mapping and long-read sequencing, to map the AMY1 region in more detail than ever before. This breakthrough allowed them to better understand how the gene duplications evolved.

Omer Gokcumen, PhD, professor of biological sciences at UB and the study’s corresponding author, explains that having more copies of the AMY1 gene allows individuals to produce more amylase, helping them digest starch more efficiently. The study, published in Science, analyzed the genomes of 68 ancient humans, including a 45,000-year-old sample from Siberia. The findings revealed that even pre-agricultural hunter-gatherers had an average of four to eight copies of the AMY1 gene per diploid cell, suggesting that high copy numbers were common long before humans began farming.

Interestingly, the research also found that Neanderthals and Denisovans, our ancient cousins, had multiple AMY1 copies, implying that the gene first duplicated over 800,000 years ago, well before modern humans split from Neanderthals.

The study highlights how early AMY1 gene duplications laid the groundwork for significant genetic variation, enabling humans to adapt to shifting diets as starch consumption increased with new technologies and lifestyles. For example,

European farmers saw a surge in AMY1 gene copies over the past 4,000 years, likely due to their starch-heavy diets. Gokcumen notes that individuals with more AMY1 copies probably digested starch more efficiently, giving them an evolutionary advantage.

This research also links AMY1 gene variation to broader themes in human evolution, genetics, and nutrition. As lead author Feyza Yilmaz from JAX points out, understanding the variation in AMY1 could provide important insights into metabolic health and the role of starch in glucose metabolism.

The study was supported by the National Science Foundation and the National Institutes of Health.

Note: The content may be simplified and reduced in size for length and readability while retaining key information. For full details, please refer to the original source.