Mutation-Biased Adaptation in a Protein NK Model

Published

October 1, 2006

Author(s)

Arlin B. Stoltzfus

Abstract

Evolutionary trends responsible for systematic differences in genome and proteome composition have been attributed to GC:AT mutation bias in the context of neutral evolution or to selection acting on genome composition. A possibility that has been ignored, presumably because it is part of neither the Modern Synthesis nor the Neutral Theory, is that mutation may impose a directional bias on adaptation. This possibility is explored here with simulations of the effect of a GC:AT bias on amino acid composition during adaptive walks on an abstract protein fitness landscape called an “NK” model. The results indicate that adaptation does not preclude mutation-biased evolution. In the complete absence of neutral evolution, a modest GC:AT bias of realistic magnitude can displace the trajectory of adaptation in a mutationally favored direction, to such a degree that amino acid composition is biased substantially and persistently. Thus, mutational explanations for evolved patterns need not presuppose neutral evolution.

Citation

Molecular Biology and Evolution

Volume

23

Issue

10

Pub Type

Journals

Keywords

mutation bias, GC content, NK model, simulation, adaptive evolution, adaptive walk

Citation

Stoltzfus, A. (2006), Mutation-Biased Adaptation in a Protein NK Model, Molecular Biology and Evolution (Accessed April 20, 2024)