Heritability Estimates of Somatotype Components Based upon Familial Data

Somatotype components were obtained in 239 French-Canadian families from Montreal. Endomorphy, mesomorphy and ectomorphy were anthropometrically assessed in the Heath and Carter system. All three components were available in 208 pairs of siblings, while only ectomorphy was estimated in 507 parent-child pairs. Sibling correlations reached 0.40 for endomorphy, 0.30 for mesomorphy, and 0.38 for ectomorphy. Partialling out the effects of 7 socioeconomic indicators permitted an estimate of common familial environment upon covariation between relatives. Residual sibling correlations yielded broad heritability estimates (HB) of 0.50 for endomorphy, 0.42 for mesomorphy and 0.54 for ectomorphy. Narrow heritability (HN) for ectomorphy, controlling for familial indicators, was approximately 0.36 including a positive contribution from assortative mating.