Gene knockin
（重定向自Knockin mouse）
In molecular cloning and biology, a knock-in (or gene knock-in) refers to a genetic engineering method that involves the one-for-one substitution of DNA sequence information with a wild-type copy in a genetic locus or the insertion of sequence information not found within the locus. Typically, this is done in mice since the technology for this process is more refined and there is a high degree of shared sequence complexity between mice and humans. The difference between knock-in technology and traditional transgenic techniques is that a knock-in involves a gene inserted into a specific locus, and is thus a "targeted" insertion.