Scientists have discovered VIPR, a powerful gene-targeting system in viruses that predates CRISPR and may be even more effective. The system, found in viruses themselves, appears to be over four billion years old and represents an evolutionary ancestor of CRISPR, according to two papers published in Science.

Unlike CRISPR, which was discovered in bacteria and other microbes as a defense against invading viruses, VIPR was found in viruses. It can target a wider variety of genetic sequences, allowing it to alter more of the genome. The molecules are also smaller, making them potentially easier to deliver into cells.

“The incredibly small size of VIPR makes these systems transformative tools for genome engineering,” said Philip Kranzusch, a microbiologist at Harvard Medical School who was not involved in the research.

Jennifer Doudna, a biochemist at the University of California, Berkeley, who shared the 2020 Nobel Prize for harnessing CRISPR, co-authored the studies. She began investigating how the natural gene editor evolved, wondering “It had to come from somewhere.” Her team, including Peter Yoon and Kenneth Loi, analyzed 2.3 million proteins to trace the origins of CRISPR-like molecules.