 In this study, researchers compared the effectiveness of two types of donor DNA for performing gene knock-in in human cells. They found that while both types of donor DNA had similar rates of successful insertion, the rate of precise insertion was higher when using double-stranded DNA, dsDNA, as opposed to single-stranded DNA, ssDNA. Additionally, they discovered that ssDNA was more likely to cause off-target insertions, which could lead to unintended mutations. This article was authored by Akira Mabuchi, Shorji Hota, Maria Jenova, and others.