On Monday, a new paper had identified a possible barrier to using the revolutionary gene-editing tool CRISPR in humans.
The news sent the stocks of all three major CRISPR biotech firms tumbling in premarket trading.
They declined by as much as 11.9 percent.
In recent years, CRISPR has been credited with the potential power to correct any number of devastating diseases.
Researchers have used it to cure mice of deadly genetic conditions like hemophilia B, Lou Gehrig's disease, and Huntington's disease.
In the U.S., the first human CRISPR trials are slated to begin this year.