The LbCas12a(D156R) entry in FlyBase represents a RNA-guided nuclease which is derived from the naturally occurring Cas12a endonuclease from Lachnospiraceae bacterium and which contains a D156R point mutation; this mutation results in LbCas12a(D156R) having a substantially higher genome editing activity compared to LbCas12a. For gene targeting, Cas12a nucleases require a short CRISPR RNA (crRNA) that contains nucleotides complementary to the genomic target site of interest, plus additional sequence required for Cas12a protein binding. Provided that a 4 nucleotide protospacer adjacent motif (PAM) sequence (TTTV) is present at the target site immediately 5' to the sequence targeted by the crRNA, then cleavage at the genomic target site can occur. Cleavage mediated by a Cas12a nuclease results in a staggered double-strand break (PMID:26422227, PMID:29843790). Cas12a nucleases also have an RNase activity that enables them to process single cRNAs from a precursor CRISPR repeat array (PMID:27918548).