Accelerating pathway evolution by increasing the gene dosage of chromosomal segments

Abstract

Significance Gene duplication and divergence are cornerstones of evolution. Genetic redundancy resulting from repeated DNA provides flexibility for transient changes in copy number that may confer selective benefit under new or changing environmental conditions. This work describes a method for creating tandem arrays of specific DNA segments in a bacterium, Acinetobacter baylyi , to accelerate experimental evolution. The induced chromosomal gene amplification mimics a natural process that would otherwise occur more slowly and stochastically. The success of this approach for the evolution of novel protein function was demonstrated with studies of an enzyme that has bioenergy applications in lignin valorization. A protein variant, which emerged from Evolution by Amplification and Synthetic biology, is beneficial in a different bacterium, indicating the broad utility of the method.