Laguna Design/SPL
Argonaute proteins (model pictured) are one of many potential alternatives to the CRISPR–Cas9 gene-editing system.
The CRISPR–Cas9 tool enables scientists to alter genomes practically at will. Hailed as dramatically easier, cheaper and more versatile than previous technologies, it has blazed through labs around the world, finding new applications in medicine and basic research.
But for all the devotion, CRISPR–Cas9 has its limitations. It is excellent at going to a particular location on the genome and cutting there, says bioengineer Prashant Mali at the University of California, San Diego. “But sometimes your application of interest demands a bit more.”
The zeal with which researchers jumped on a possible new gene-editing system called NgAgoearlier this year reveals an undercurrent of frustration with CRISPR–Cas9 — and a drive to find alternatives. “It’s a reminder of how fragile every new technology is,” says George Church, a geneticist at Harvard Medical School in Boston, Massachusetts.