Functional mapping: How to map genes for phenotypic plasticity of development

Functional mapping is a statistical tool derived to map genes or quantitative trait loci (QTLs) that control the dynamic process of complex traits. In this chapter, we describe an innovative modification of functional mapping to characterize the genetic basis of phenotypic plasticity for the developmental pattern of phenotypic traits. Phenotypic plasticity is a phenomenon by which multiple phenotypes are produced by a single genotype in response to changing environment. Although phenotypic plasticity has been extensively studied in the past decades, new insights into its formation mechanisms can be gained by integrating developmental principles because environmentally induced phenotypes require time to form and build. The new framework for functional mapping enables geneticists to illustrate the genetic architecture of how QTLs cope with environment to regulate the developmental pattern and timing of phenotypic formation. Because of their role in guiding the evolution of complex phenotypes through environmental adaptation, the discoveries of these QTLs facilitate the synthesis of evo-devo and eco-devo.