Familial transmission of longevity.

The Tau model of phenotypic transmission has been used to analyze the familial correlations (nuclear families and extended families) of longevity at Arthez d'Asson (individuals born between 1686 and 1899). At birth, the transmissibility (t2) is very weak: 0.103; at 20 years old, t2 = 0.167; at 50 years old, t2 = 0.294. The effect of sibling environment on children's phenotype is s = 0.086 at birth, is thus null. A cohabitional effect between spouses: p = 0.167 appears after 50 years. There is no social homogamy effect via grandparents.