Computer illustration showing the molecular structure of the CRISPR-associated protein Cas9 in complex with RNA (ribonucleic acid, red) and DNA (deoxyribonucleic acid, orange-fuchsia). Cas9 is a nuclease protein associated with the CRISPR (Clustered Regularly Interspersed Palindromic Repeats) adaptive immunity system in Streptococcus pyogenes and other bacteria. It uses a guide RNA sequence to cut DNA at a complementary site. Seen here: Cas9 alpha-helical lobe (grey), HNH domain (blue), RuvC domain (light blue), C-terminal-domain (pink), topo homology domain (pale pink), arginine-rich helix (light fuchsia), guideRNA (red), target DNA (orange), non-target DNA (fuchsia). | Ramon Andrade 3DCiencia/Science Photo Library/Getty Images

CRISPR’s ‘Off-Target Effects’ May Just Be Genetic Drift

A leading journal retracted a 2017 paper that implicated CRISPR-Cas9 in causing unintended genetic mutations.

Updated On 04/20/2018 at 04:11PM EST
4:32 PM EDT
L L ast June, Seeker posted a story about a startling paper published in the journal Nature Methods that identified 1,600 accidental mutations in the genomes of mice treated with the gene-editing tool CRISPR-Cas9. The revelation caused stock prices to drop at biotech companies developing CRISPR gene therapies. But the paper also quickly came under fire for its experimental design, which some CRISPR supporters said was faulty.