How Potatoes Shaped the Genes of the First People to Grow Them
If you chew a brine long enough, it starts to taste sweet. This is because the amylase enzyme present in your saliva breaks down complex starch into simple sugars. How quickly this reaction occurs depends on how much of the enzyme you have in your sputum, which is determined by how many copies of the amylase gene you have. And there is a lot of variability in copy number between different populations. Concrete example: according to a new study published in Natural communicationsthe Quechua people of the Andes have many examples, and that’s probably because they were the first to domesticate the humble potato.
To study the evolutionary history of the amylase gene, biologists at the University at Buffalo collected DNA from Quechua speakers from the Peruvian Andes and compared it to genomic databases containing samples from thousands of other groups. They discovered that the Quechua carry an average of 10 copies of the amylase gene. The Mayan people of Mexico, a genetically similar population without the long history of eating Quechua potatoes, have an average of six examples.
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“Biologists have long suspected that different groups of humans have evolved genetic adaptations in response to their diet, but there are very few cases where the evidence is this strong,” study co-author Omer Gokcumen explained in a statement.
Of course, it’s not the potatoes themselves that change our genetics, it’s natural selection. The Quechua people domesticated the potato about 10,000 years ago, and in the generations that followed, those with more copies of amylase had more offspring. “Evolution is about chiseling a sculpture, not building a building,” Gokcumen said.
However, on the scale of evolution, 10,000 years is only the blink of an eye, and these ancient Peruvians seem to have adapted very quickly to their new diet. Researchers say this shows how malleable our metabolic genes are in the hands of evolution. “Our metabolic pathways are not simply a product of this Paleolithic past,” said study co-author Abigail Bigham.
In other words, people on a paleo diet can treat themselves to a fry every once in a while.
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Main image: Curioso.Photography / Adobe Stock
