Nature Biotechnol. doi:10.1038/nbt1409 (2008) and Nature Biotechnol. doi:10.1038/nbt1398

Two groups have developed a method to pick and choose the genes they disrupt in zebrafish using chimaeric enzymes called zinc-finger nucleases.

These enzymes cause double-stranded breaks in DNA when two of them join — and because they contain several zinc fingers that are each specific to a different triplet of DNA bases, enzymes can be engineered to target unique sequences in a genome.

Sharon Amacher at the University of California, Berkeley, and her colleagues used nucleases with four zinc fingers and observed no DNA breaks other than those they intended. The other team, led by Scot Wolfe and Nathan Lawson at the University of Massachusetts Medical School in Worcester, used three-finger nucleases and found off-target cleavage in 1–5% of zebrafish.