Practice question

CRISPR systems are classified into Class 1 with multi-protein effector complexes and Class 2 with single large effector protein mediating interference. Class 1 includes Types I, III, IV requiring Cascade complex for targeting. Class 2 includes Types II, V and VI containing Cas9, Cas12 and Cas13 respectively. Single effector architecture simplifies repurposing for genome editing since one protein plus guide RNA suffices. This distinction based on effector complexity explains why Cas9 dominates biotechnology despite natural diversity of CRISPR mechanisms across bacteria and archaea.