Lifespan More Genetically Wired Than We Realized, New Study Finds

A new Science study estimates that about 55% of human lifespan is heritable, roughly double previous estimates, after carefully separating intrinsic genetic factors from extrinsic causes of death. By analyzing twin data, varying age cutoffs, and corroborating with Scandinavian twins and American centenarian siblings, researchers show that reducing extrinsic mortality reveals the stronger genetic signal and that aging-related frailty can blur it. The finding reshapes how aging research is funded and pursued, and points to the search for specific genetic variants that govern intrinsic aging.