VATIS UPDATE Article

A huge genetic study done by researchers at Columbia University, the United States, on finding how the human genome is evolving suggests that natural selection is getting rid of harmful genetic mutations that shorten people’s lives. The work analysed DNA from 215,000 people and is one of the first attempts to probe directly how humans are evolving over one or two generations.

To identify which bits of the human genome might be evolving, researchers scoured large US and UK genetic databases for mutations whose prevalence changed across different age groups. For each person, the parents’ age of death was recorded as a measure of longevity, or their own age in some cases. “If a genetic variant influences survival, its frequency should change with the age of the surviving individuals,” said Hakhamanesh Mostafavi, at Columbia University.

People who carry a harmful genetic variant die at a higher rate, so the variant becomes rarer in the older portion of the population. Researchers tested more than 8 million common mutations, and found two that seemed to become less prevalent with age. A variant of the APOE gene, which is strongly linked to Alzheimer’s disease, was rarely found in women over 70. And a mutation in the CHRNA3 gene associated with heavy smoking in men petered out in the population starting in middle age.