Genetic and environmental sources on familial transmission in Basque families. II. Stature, weight and body mass index

Abstract

Primary objective : The present research analyses a cross-sectional sample of 359 individuals (107 fathers, 107 mothers, 71 sons and 74 daughters) in 107 nuclear families from the Basque Country (Spain). The aim was the estimation of both transmissible and non-transmissible components acting on familial resemblance for stature, weight and body mass index (BMI). Methods : Standardized data of each generation and sex were adjusted to a BETA model of path analysis independent of sex effects, allowing the possibility of differentiating between transmissible (genetic and cultural) and non-transmissible (environmental) components acting on the observed phenotypic variance in Biscayan offspring. Results : The results supported the full model of familial transmission for the three variables, in addition to other reduced models that gave rise to transmission effects regardless of any influence from the siblings' shared environment on the environmental transmitted component from their parents ( b = 0), and without genetic effects on the phenotype ( h = z = 0). The most parsimonious model was accepted for weight and rejected for stature and BMI. The correlations existing between children and their mothers were higher than those with their fathers. Conclusion : The results confirmed the hypothesis of maternal effects influencing the inheritance of stature.