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Decay of unused characters by selection and drift
Author(s) -
HALL A. R.,
COLEGRAVE N.
Publication year - 2008
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2007.01473.x
Subject(s) - biology , selection (genetic algorithm) , character (mathematics) , context (archaeology) , experimental evolution , resource (disambiguation) , evolutionary biology , ecology , genetic fitness , genetic drift , stabilizing selection , biological evolution , genetic variation , genetics , artificial intelligence , computer science , gene , mathematics , paleontology , computer network , geometry
The reduction and loss of redundant phenotypic characters is a common feature of evolution. However, the mechanisms that drive deterioration of unused characters remain unclear. Here, we outline a simple framework where the relative importance of selective and neutral processes varies with environmental factors, because of variation in the fitness costs associated with unused traits. We tested our hypotheses using experimental evolution of the bacterium Pseudomonas fluorescens in spatially uniform environments. Results show that an unused character, swimming motility, decayed over evolutionary time and the rate of this decay varied among selection environments with different levels of resource availability. This is explained in the context of an environment‐specific genetic correlation between motility and fitness, which is negative when resources are limited but neutral at higher resource levels. Thus, selection against an unused character was most effective in environments where the fitness cost was the greatest. This suggests that the same character can decay by different mechanisms depending upon environmental factors and supports previous evidence to show that resource availability can critically affect the outcomes of evolution.