Genetic and environmental factors in the variability of somatotype components of siblings

Abstract

The aims of this study were to determine the influence of genetic and environmental factors in siblings variation in somatotype components, as well as to present a sequence of didactic steps when conducting a Quantitative Genetic analysis. The sample is comprised of 366 sibling pairs aged from 10 to 18 years of age residing in the northeast of Portugal. Somatotype components were estimated according to Carter & Heath (1990) protocol based on 10 somatic measurements. Exploratory data analysis was done in SPSS and PEDSTATS. Genetic factors were estimated in the SAGE software. Results showed a high quality of data available (technical error of measurement ≈1%). Mesomorphy was the most salient component is physique structure of siblings, being it brother-brother, sister-sister, or brother-sister. Even when adjusted for covariates, genetic factors are high: 0.49 for endomorphy, 0.55 for mesomorphy, and 0.71 for ectomorphy. These results suggest that substancial genetic factors govern somatotype variation in the population.