canalization

Green RM, Fish JL, Young NM, Smith FJ, Roberts B, Dolan K, Choi I, Leach CL, Gordon P, Cheverud JM, Roseman CC, Williams TJ, Marcucio RS & Hallgrímsson B 2017 Developmental nonlinearity drives phenotypic robustness. Nat Commun 8:1970.

• excess production of important proteins has been suggested as an explanation for canalization⁵⁹ and is also the basis for Sewall Wright's hypothesis for the developmental basis of dominance

• a key challenge in evolutionary developmental biology is to relate the quantitative genetic theory that underpins evolutionary biology to developmental mechanisms
• in quantitative genetics, gene interactions generate epistasis
• canalization can evolve by selection on epistatic variance
• once a nonlinearity occurs in development, it will generate gene interactions if the differential variation along the curve is heritable
• seen in this light, developmental nonlinearities are a cause rather than a consequence of epistasis
• epistasis is widely thought to contribute to missing heritability for complex traits because it can cause similarity among relatives not accounted for in QTL or GWAS studies
• the developmental basis for canalization is central to both the evolvability and the genetics of complex traits