Robustness increases heritability: implications for familial disease.

Robustness protects organisms in two ways. Homeostatic buffering lowers the variation of traits caused by internal or external perturbations. Tolerance reduces the consequences of bad situa- tions, such as extreme phenotypes or infections. This article shows that both types of robustness increase the heritability of protected traits. Additionally, robustness strongly increases the heri- tability of disease. The natural tendency for organisms to protect robustly against perturbations may partly explain the high heritability that occurs for some diseases.