Genes Drive About Half of Human Lifespan, New Study Finds

A study in Science argues that genetics accounts for roughly 50% of variation in human lifespan after removing the masking effect of extrinsic mortality (accidents, disease, etc.), suggesting genes governing ageing are substantial contributors. Using a math model and twin data from Denmark and Sweden, the researchers found heritability around 50% and noted that as environmental risks declined over the 20th century, genetic influence becomes more evident. The work implies future therapies could target ageing mechanisms, though lifestyle and environment still play a major role, varying by cause of death and age.