Definition: mouse models with single or multiple base changes or an exogenous gene introduced into the target gene position.
Principle: Knockins introduce specific mutation(s) or an exogenous gene in the target gene position. For example, this method can introduce point mutation(s), which can simulate a human genetic disease, in the target gene. It can also be used to introduce a reporter gene (such as EGFP, mRFP, mCherry, mYFP or LacZ, etc.) or functional cDNA (such as Cre and Dre, etc.) to be expressed in a specific locus by homologous recombination, thereby making the expression of the reporter gene or other cDNA accordant with the expression of the target gene. The knockout and knockin occurs at the same time when the reporter gene or cDNA replaces the mouse gene.