DEVELOPMENTAL QUANTITATIVE GENETIC MODELS OF EVOLUTIONARY CHANGE

Discussions about evolutionary change in developmental processes or mo rphological structures are predicated on specific quantitative genetic models whose parameters predict whether evolutionary change can occur , its relative rate and direction, and if correlated change will occur in other related and unrelated structures. The appropriate genetic mo del should reflect the relevant genetical and developmental biology of the organisms, yet be simple enough in its parameters so that deducti ons can be made and hypotheses tested. As a consequence, the choice of the most appropriate genetic model for polygenically controlled trait s is a complex tissue and the eventual choice of model is often a comp romise between completeness of the model and computational expediency. Herein, we discuss several developmental quantitative genetic models for the evolution of development and morphology. The models range from the classical direct effects model to complex epigenetic models. Furt her, we demonstrate the algebraic equivalency of the Cowley and Atchle y epigenetic model and Wagner's developmental mapping model. Finally, we propose a new multivariate model for continuous growth trajectories . The relative efficacy of these various models for understanding evol utionary change in developmental and morphological traits is discussed . (C) 1994 Wiley-Liss, Inc.