The alternative method, called prime editing, improves the chances that researchers will end up with only the edits they want, instead of a mix of changes that they can’t predict. The tool, described in a study published on 21 October in Nature¹, also reduces the ‘off-target’ effects that are a key challenge for some applications of the standard CRISPR–Cas9 system. That could make prime-editing-based gene therapies safer for use in people.

https://www.nature.com/articles/d41586-019-03164-5