Data for "Phenotypic convergence in growth performance peaks at mildly cold, not optimal-for-growth, temperatures"

The fitness effects of mutations that impact rate-limiting processes may be mitigated at warmer temperatures, which however may unmask genetic variation relevant to protein stability. Therefore, intermediate, benign, thermal conditions may allow for greater phenotypic robustness and maintain more genetic variation. It is unknown whether temperatures maximizing phenotypic convergence coincide with those optimizing growth rate. Here in our study with experimental evolution lines of two model bacteria (Escherichia coli and Pseudomonas fluorescens), independent genotypes showed the lowest variability in maximum growth rate at temperatures colder than the optimal-for-growth conditions (about 2-13℃ lower). We then performed an analysis based on previously published data, showing that among-species convergence in several vital biological processes also consistently peaked at temperatures lower than that optimizing the rates of those processes. These results suggest that environments cooler than growth optima may serve as reservoirs of genetic diversity which may be eroded by global warming.