Figure 1.

Mutant library types and massively parallel sequencing‐resolved assays for high‐throughput genotype–phenotype mapping. Bulk mutagenesis is used to construct an in vitro or in vivo genotype library, with the phenotype(s) of interest associated with the genotype either by “display” or encapsulation. Phenotypic measurements are then linked to genotypes by deep‐sequencing of the library before and after some selection procedure. Selection procedures include binding to a target for direct binding phenotypes, particle sorting for any optically assayable phenotype (e.g. fluorescence or cell dimensions) and simple propagation under selective conditions for competitive fitness. Filled rectangles (straight or curved): nucleic acids; filled circles: proteins. Illustrated library examples are named in bold