Mechanisms of Phenotypic Evolution from Molecules to Organisms: Integrating Evolutionary Biochemistry and...

Evolutionary developmental biology (evo-devo) and evolutionary biochemistry share a common goal: to understand the causes of phenotypic evolution in terms of the mechanisms that translate genetic sequence information into developmental outcomes or the structure/function of macromolecules. Although dialog between the two fields has been limited, they share a common conceptual foundation and have converged upon many similar conclusions about the causes and dynamics of evolutionary change. By assessing major findings from both fields, we identify common properties of the genotype-phenotype relationship that characterize both biochemistry and development: tinkering with ancestral forms, nonlinear transformations, variable degeneracy, pleiotropy, and epistasis. In turn, these shared properties produce similarities in the evolutionary processes that produce biological diversity across levels, including major roles for large-effect mutations, historical contingency and entrenchment of derived forms, systems drift, convergence on non-optimal properties, and directionality in phenotypic evolution. The common foundations of evo-devo and evolutionary biochemistry also set the stage for a practical integration of their research programs, which would explicitly characterize how genetic evolution causes biochemical evolution, which in turn causes the evolution of development. An integrated view of evo-devo and evolutionary biochemistry promises a more complete mechanistic understanding of how evolution across the hierarchy of biological causality has produced the astonishing diversity and complexity of biological phenotypes.