Genetic mutation has evolved to cope with modern diets high in sugar

The variant of the gene has become more common in humans after cooking and agriculture is widespread and could help people avoid diabetes, according to the findings published in eLife.

"We found that people differed in how effectively their bodies could manage blood sugar, resulting from an evolutionary process that seems to have been brought on by a regime change," said the principal author of Study, Frances Brodsky, director of UCL Biosciences.

The researchers studied the CLTCL1 gene, which directs the production of the CHC22 protein that plays a key role in regulating the glucose transporter in our fat and muscle cells.

Once people eat, insulin, a hormone that responds to higher blood glucose levels, releases the carrier to extract glucose from the blood and introduce it into muscles and adipose tissue. Between meals, using the CHC22 protein, the glucose transporter stays inside the muscles and fat, allowing the blood glucose to continue to circulate.

The research team, composed of specialists in population genetics, evolutionary biology, ancient DNA and cell biology, analyzed human genomes as well as those of 61 other species, in order to understand how the gene producing CHC22 has varied over the course of evolution history.

In humans, by examining the genomes of 2,504 people in the 1000 Genomes global project, they found that nearly half of the people in many ethnic groups had a variant of CHC22 produced by a mutated gene, which was becoming increasingly common. more common as people developed. cooking and agriculture.

The researchers also examined ancient human genomes and found that the most recent variant was more prevalent among older and modern agricultural populations than among hunter-gatherers, suggesting that increased carbohydrate consumption could have been the selective force that drove the genetic adaptation.

By studying the cells, the researchers discovered that the new CHC22 variant is less effective at keeping the glucose transporter in muscles and fat between meals, which means that the carrier can more easily remove glucose from the blood. People with the most recent variant will therefore have a lower blood sugar.

"The older version of this genetic variant would probably have been useful to our ancestors, because it would have allowed to maintain higher blood sugar levels during periods of fasting, when we did not have access also easy to carbs, which would have helped us to evolve our big brains, "said the first author, Dr. Matteo Fumagalli, who began studying at UCL before joining the company. Imperial College London.

"In recent years, with our high carbohydrate diets that often provide us with too much sugar, the new variant could be beneficial," added Dr. Fumagalli.

The researchers say that although this genetic variant does not play a direct role in the development of diabetes, the fact that it is older can increase the risk of developing diabetes and can also exacerbate resistance to diabetes. insulin involved in diabetes.

"People with the older variant may need to pay more attention to carbohydrate intake, but more research is needed to understand how the genetic variant found may affect our physiology," added Professor Brodsky.

Co-author Mark Thomas (UCL Genetics, Evolution & Environment), added: "Our analyzes strongly suggest that we have found another example of how prehistoric changes in dietary habits have shaped human evolution Understanding how we have adapted to these changes Not only informing us of why people lived or died in the past, but also helping us better understand the relationship between diet, health and illness today .