From our worm colleagues--article of possible interest to folks working with CRISPR system:
van Schendel R, Roerink SF, Portegijs V, van den Heuvel S, Tijsterman M. Polymerase Θ is a key driver of genome evolution and of CRISPR/Cas9-mediated mutagenesis. Nat Commun. 2015 Jun 16;6:7394. PMID: 26077599.
From the abstract: "... Here, we demonstrate that the A-family polymerase theta (POLQ) is a major driver of inheritable genomic alterations in Caenorhabditis elegans. Unlike somatic cells, which use non-homologous end joining (NHEJ) to repair DNA transposon-induced DSBs, germ cells use polymerase theta-mediated end joining, a conceptually simple repair mechanism requiring only one nucleotide as a template for repair. Also CRISPR/Cas9-induced genomic changes are exclusively generated through polymerase theta-mediated end joining, refuting a previously assumed requirement for NHEJ in their formation. ... "