CRISPR-Cas9 breaks genes better if you disrupt DNA repair

The popular gene-editing tool CRISPR-Cas9 competes with DNA repair, continually cutting what repair enzymes fix until the enzymes make a mistake, resulting in a broken gene. This led to a trick to improve cutting efficiency of the Cas9 protein. By dumping random bits of non-homologous DNA into the cell with Cas9, they disrupted the DNA repair process and boosted knockout efficiency up to five fold in human cell lines.