A team led by Caixia Gao at the Chinese Academy of Sciences has uncovered the evolutionary origin of Type V CRISPR-Cas systems (Cas12 enzymes) revealing that functional RNA splitting events transformed mobile genetic elements called IS200/605 transposons into CRISPR systems. By mining prokaryotic and metagenomic databases, they identified intermediate transposon-CRISPR hybrid clades termed TranCs that use CRISPR RNAs to target DNA. This discovery, published in Cell, illuminates the molecular mechanisms bridging transposons and adaptive immune systems essential for genome editing technologies.