Overview
- Nature Communications published a multi-institutional study co-led by UCLA and the University at Buffalo that traces how a starch-digesting gene rose in frequency in the Andes.
- The authors link the shift to the era when potatoes became a staple in the highlands 6,000–10,000 years ago, with people carrying roughly 10 or more copies gaining about a 1.24% per-generation edge.
- Descendants in Peru now average around 10 copies of the gene, exceeding all other sampled populations and outpacing the Maya, who average about six.
- More copies are tied to higher levels of salivary amylase, which starts breaking down starch in the mouth and may also influence the gut microbiome as diets change.
- Ultra-long DNA sequencing and comparisons across dozens of populations show the selection signal predates European contact, helping rule out post-contact population collapse as the main cause.