Knockout: a knockout alleleplugin-autotooltip__default plugin-autotooltip_bigAllele: a version of a gene. Alleles of a gene are different if they have differences in their DNA sequence. is a nullplugin-autotooltip__default plugin-autotooltip_bigAmorphic mutation: assuming a wildtype allele has 100% gene function, an amorphic mutation is a mutant allele that has 0% gene function. Also called a null mutation or a complete loss of function mutation. alleleplugin-autotooltip__default plugin-autotooltip_bigAllele: a version of a gene. Alleles of a gene are different if they have differences in their DNA sequence. generated through reverse geneticsplugin-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.