Researchers at Israel's Weizmann Institute of Science have determined that genetics explain about 50% of differences in human lifespan, far more than previously estimated. The finding, published in the journal Science, challenges earlier views that placed genetic influence at 20-25% or less. By analyzing twin data and filtering out external death causes, the team uncovered this stronger hereditary role.
A team led by Ben Shenhar in Prof. Uri Alon's lab at the Weizmann Institute analyzed twin databases from Sweden and Denmark, including twins raised apart. Previous studies underestimated genetics because they did not separate deaths from aging—termed intrinsic mortality—from extrinsic causes like accidents and infections. Using mathematical models and simulations of virtual twins, the researchers isolated these factors, revealing heritability around 50% for lifespan variation overall. For dementia deaths up to age 80, heritability reaches about 70%, exceeding that for cancer or heart disease. Ben Shenhar noted, 'For many years, human lifespan was thought to be shaped almost entirely by non-genetic factors, which led to considerable skepticism about the role of genetics in aging.' This higher heritability, aligning with patterns in other traits and animal studies, could spur efforts to identify lifespan-extending gene variants. Shenhar added that it 'creates an incentive to search for gene variants that extend lifespan, in order to understand the biology of aging and, potentially, to address it therapeutically.' The study appears in Science under the title 'Heritability of intrinsic human life span is about 50% when confounding factors are addressed.'
