Abstract

Evolution underpins and relates all the diversity of life on Earth. The fuel of evolution is phenotypic or functional variation and despite the huge successes of evolutionary theory over the past century there is a glaring omission, which is still yet to be fully addressed, and that is the ability to predict what variation can arise. In this talk I will consider simple models of genotype-phenotype maps based on biophysical principles and how redundancy/entropy of the mapping interplays with genetic drift (finite population size fluctuations), and leads to non-optimality in a very general way. A classic example is the empirically observed marginal stability of proteins, for which many apaptionist explanations have been proposed — however, when viewed from the perpspective of genotype-phenotype maps, it is simply a consequence of a balance between competing forces of selection and genetic drift — amplified by the entropy phenotypes — countering the adaptionist narrative that marginal stability has evolved for a specific purpose. I will then explore some of the predictions of such models, including how speciation can become more rapid for smaller populations.