Evidence of sex-linked effects on the inheritance of human longevity: a population-based study in the Valserine valley (French Jura), 18-20th centuries

A long-standing puzzle in gerontology is the sex dependence of human longev ity and its inheritance. We have analysed the sex-linked pattern of inherit ance of longevity from 643 nuclear families on the historical population re gister of a French valley. We have focused on mean conditional life expecta ncy at a minimum age of 50 years, thus, in the present study, longevity ref ers to late or post-reproductive survival. A comparison of parents' and off spring's longevity has shown the existence of a heritable component of late survival in this population. We have found that the heritable component wa s substantially larger for daughters compared to sons. Moreover, this resul t appeared to be specific to late survival, that is, when only post-reprodu ctive mortality for parental and offspring generations is taken into accoun t. The stronger resemblance of parents to their daughters was no longer obs erved when considering younger ages at death for the offspring. This observ ation explains the hitherto unaccountable diversity of data in previous stu dies.