CRISPR-Cas12, also known as Cpf1, was characterized as a genome editing tool by Feng Zhang's group at the Broad Institute in 2015. Unlike Cas9, which creates blunt-ended cuts and requires two RNA components, Cas12 uses a single guide RNA (crRNA) and generates staggered cuts with 5-prime overhangs. It also recognizes a T-rich PAM sequence on the 5-prime side of the target, complementing the G-rich PAM preference of Cas9 and expanding the range of targetable genomic sites.
Mammoth Biosciences has made Cas12 a cornerstone of its platform, developing both therapeutic editing and diagnostic applications. The collateral cleavage activity of Cas12, where activated Cas12 non-specifically degrades single-stranded DNA after target recognition, has been harnessed for the DETECTR diagnostic system. This approach enables rapid, sensitive detection of specific DNA sequences without expensive laboratory equipment, with applications ranging from infectious disease testing to agricultural pathogen monitoring.
The Cas12 family has expanded significantly through metagenomic discovery efforts. Researchers have identified Cas12 variants with diverse properties, including hypercompact versions suitable for viral delivery and variants with altered PAM requirements. These discoveries, many emerging from environmental DNA sequencing of previously uncultured microorganisms, continue to enrich the CRISPR toolkit. The diversity of Cas12 enzymes provides synthetic biologists and therapeutic developers with an expanding palette of editing tools optimized for different applications and delivery constraints.