Dec 14, 2017

Sexual recombination and increased mutation rate expedite evolution of Escherichia coli in varied fitness landscapes

Nature Communications
George L Peabody VKaty C Kao

Abstract

Sexual recombination and mutation rate are theorized to play different roles in adaptive evolution depending on the fitness landscape; however, direct experimental support is limited. Here we examine how these factors affect the rate of adaptation utilizing a "genderless" strain of Escherichia coli capable of continuous in situ sexual recombination. The results show that the populations with increased mutation rate, and capable of sexual recombination, outperform all the other populations. We further characterize two sexual and two asexual populations with increased mutation rate and observe maintenance of beneficial mutations in the sexual populations through mutational sweeps. Furthermore, we experimentally identify the molecular signature of a mating event within the sexual population that combines two beneficial mutations to generate a fitter progeny; this evidence suggests that the recombination event partially alleviates clonal interference. We present additional data suggesting that stochasticity plays an important role in the combinations of mutations observed.

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Citations

Mentioned in this Paper

Alkalescens-Dispar Group
Recombination, Genetic
Clone
Adaptation
Genetic Fitness
Febrile Convulsions
Escherichia coli
Molecular Signature
Bacterial Conjugation
Mutation Abnormality

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