Gene Editing 20 Years Later

Abstract

Directed modification of the genome is critical for interrogating gene function and can also be applied for gene therapy. Two decades ago a double-strand break (DSB) in the genome was discovered to induce efficient gene modification, either by homologous recombination with introduced DNA, i.e., gene targeting, or imprecise joining of DNA ends leading to mutagenesis. The accelerating development of technologies—meganucleases, ZFNs, TALENs, and CRISPR/Cas9— to introduce DSBs at specific sites in the genome for the purposes of modification is revolutionizing the biological and biomedical sciences. This chapter provides an overview of the research that led to these advances in gene editing and also summarizes DSB repair mechanisms in mammalian cells.