Fortunately, cells possess the machinery to perform a second type of repair, one that is far more precise and controlled than merely gluing broken DNA back together. Instead of joining DNA segments unrelated in sequence, this alternative mode—a pathway that early gene-editing researchers used to their advantage—exclusively rejoins segments that are similar in sequence. This pickiness explains the two synonymous terms that refer to this process: homologous recombination and homology-directed repair.
