Salk Institute scientists have mapped out a CRISPR enzyme called Cas13d that has the ability to target and edit RNA, opening the way for even more precisely-calibrated genetic therapies. This builds on research into Cas9, another CRISPR enzyme that allows them to repair defects and mutations within individual cells, but which may cause dangerous collateral damage such as leaving modified cells more vulnerable to cancer. Cas13d's interaction with RNA allows scientists to alter gene activity without permanently rewriting the gene itself. Key Takeaways: Recently, CRISPR-Cas9 became popular when it was found that it could edit genetic code so as to correct cellular defects. Despite the advantages, it has been found that CRISPR'ed cells could initiative tumors because they lack a key anti-cancer mechanism. Scientists consider it a good option to explore a way to modify a gene's activity without permanent or dangerous consequences. "Specifically, Cas9 enzymes act sort of like scissors,