Leading the dog of selection by its mutational nose

Abstract

There are two simple caricatures of evolutionary dynamics: the phenotypic caricature focuses on continuous and predictable selection on variability of quantitative traits, whereas the genotypic caricature focuses on discrete, stochastic mutations. Although the apparent contradictions between these pictures were reconciled long ago, our quantitative understanding of the interplay between them is still surprisingly primitive. Indeed, even the simplest models of the dynamics of large asexual populations in which many alleles and many new mutations contribute to the evolving fitness have resisted solution. The PNAS paper by Hallatschek (1) is a substantial advance in the development of the mathematical methods needed to analyze these and more complex models.