Knock-in: a reverse geneticplugin-autotooltip__default plugin-autotooltip_bigReverse genetics: an approach to studying genes wherein a researcher starts with knowledge of the physical identity of a gene (i.e., the DNA sequence of the gene) but does not know its function. In reverse genetics, the researcher uses various molecular genetic tools to create modified alleles that are reintroduced into an organism, with the goal of trying to deduce the function of the experimental approach that replaces an endogenous copy of a geneplugin-autotooltip__default plugin-autotooltip_bigGene: read Chapters 02, 03, 04, 05, and 06 for a definition of gene :-) with a modified one.