Humans are continuing to evolve, accruing changes in genes associated with Alzheimer's disease, puberty timing, and more, Newsweek reports.
Columbia University's Joseph Pickrell and his colleagues examined data from large cohorts like the Genetic Epidemiology Research on Adult Health and Aging and the UK Biobank cohorts to search for alleles whose frequencies vary across ages. If certain alleles are less common among those with longer lifespans, natural selection could be removing them from the population.
As they report in PLOS Biology, the researchers found that variants near the Alzheimer's-linked APOE gene and the smoking-associated CHRNA3 gene affected viability and were less frequent among long-lived people. Similarly, they report that people with variants associated with deleted puberty timing had parents who typically had lived longer. Newsweek notes that a one-year delay in puberty was associated with a reduced death rate of between three percent and four percent.
Pickrell and his colleagues also found that genetically predicted higher cholesterol levels, body mass index, coronary artery disease risk, and asthma risk were each associated with declines in survival.
"It's a subtle signal, but we find genetic evidence that natural selection is happening in modern human populations," Pickrell says in a statement.