TY - JOUR T1 - Increasing growth rate slows adaptation when genotypes compete for diffusing resources A1 - Chacón, Jeremy M. A1 - Shaw, Allison K. A1 - Harcombe, William R. Y1 - 2020/01/07 N2 - Author summary What determines how quickly a beneficial mutation will spread through a population? The intuitive answer is that mutations that confer faster growth rates will spread at a rate that is relative to the size of the growth-rate benefit. Indeed, this is true in a well-mixed environment where all genotypes compete globally. But most organisms don’t live in a simple well-mixed environment. Many organisms, like bacteria, live in a structured environment, such as on the surface of a solid substrate. Does life on a surface change the expectation about the spread of faster-growing mutants? We developed a mathematical model to answer this question, and found that on a surface, the actual growth rates—not just the relative growth rates—were critical to determining how fast a faster-growing mutant spread through a population. When the simulated organisms grew slowly, competition was basically global and a faster-growing mutant could pre-empt resources from far-away competitors. In contrast, when organisms grew more quickly, competition became much more localized, and the faster-growing mutant could only steal resources from neighboring competitors. This result means that there are diminishing returns to series of mutations which confer growth-rate benefits. This idea will help us predict and understand future and past evolutionary trajectories. JF - PLOS Computational Biology JA - PLOS Computational Biology VL - 16 IS - 1 UR - https://doi.org/10.1371/journal.pcbi.1007585 SP - e1007585 EP - PB - Public Library of Science M3 - doi:10.1371/journal.pcbi.1007585 ER -