High-throughput directed evolution: a golden era for protein science

Directed evolution is a robust and powerful tool for engineering new and/or improved functions in biomolecules for therapeutic and industrial applications, as well as to uncover fundamental insights into protein behaviour. It works by exploiting the principle of natural evolution and accelerating it through multiple rounds of gene diversification and selection. To evolve the desired property, an appropriate assay for the property of interest must be chosen. Here, we describe recent advances in the development of in vitro and in vivo diversification methods, as well as high-throughput assays for protein directed evolution. Using recent examples, we discuss the drawbacks and challenges of the array of diversification methods and selection assays and consider future challenges in the field.