Discovery of CRISPR's long lost ancestor may expand gene-editing toolkit

CRISPR may be a powerful technology for gene editing, but the system existed in bacteria long before scientists began using it. For billions of years, CRISPR has acted as a natural immune system in bacteria and other microbes, helping defend them against invading viruses. But now, two new studies, published in Science, describe a similar RNA-guided system that originated in the viruses themselves and appears to be a precursor to CRISPR.

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