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Updated: Jan 25, 2026

Substrate Generation for Endonucleases of CRISPR/Cas Systems
Published on: September 8, 2012
Classification and Nomenclature of CRISPR-Cas Systems: Where from Here?
Kira S Makarova1, Yuri I Wolf1, Eugene V Koonin1
1National Center for Biotechnology Information , National Library of Medicine, Bethesda, Maryland.
Abstract:
As befits an immune mechanism, CRISPR-Cas systems are highly variable with respect to Cas protein sequences, gene composition, and organization of the genomic loci. Optimal classification of CRISPR-Cas systems and rational nomenclature for CRISPR-associated genes are essential for further progress of CRISPR research. These are highly challenging tasks because of the complexity of CRISPR-Cas and their fast evolution, including frequent module shuffling, as well as the lack of universal markers for a consistent evolutionary classification. The complexity and variability of CRISPR-Cas systems necessitate a multipronged approach to classification and nomenclature. We present a brief summary of the current state of the art and discuss further directions in this area.
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