“Familiality” or Heritability

Abstract

Comments on an article by L. E. Hong and A. Summerfelt et al. (see record 2008-18377-004). The commentators stated that heritability reflects the proportion of overall variability in a trait in a population that results from additive genetic effects. Within human populations, such estimates have traditionally relied on special relationships that can disentangle genetic from familial-environmental effects. The most popular of these methods have been twin studies comparing monozygotic and dizygotic twin pairs and various adoption designs. Heritabilities are estimated from sibling-sibling and parent-offspring pairs using the program SOLAR. Given that there may be considerable sharing of environmental factors for both of these relationships, the assumption that their effects are absent is hard to justify for many phenotypes. (PsycINFO Database Record (c) 2013 APA, all rights reserved).