About Neurogenomics
Mouse Lines
Research Vocabulary
In This Section



Preliminary Assessments


Learning and Memory

Psychostimulant Response

Circadian Rhythmicity

Vision and Eye


Center for Functional Genomics at Northwestern University

National Institutes of Health

Protocols ›› Breeding Schemes

The mutagenized (G0) mice are not expected to show abnormal phenotypes, but they can be bred with a normal female to generate G1 offspring that are heterozygous for mutations induced in the G0 male. In order to create animals that are homozygous for mutations carried by the G1 males 2 further generations of breeding are required to produce G3 animals.

Click on the image to see an enlarged version

Breeding schemes to detect recessive mutations in third-generation (G3) offspring. In the backcross scheme , G1 male progeny are mated with wild-type females to produce second-generation (G2) progeny. The female G2 progeny are then bred with their G1 father to produce G3 progeny. Dominant and semidominant mutations are expressed in an average of 75% of the G3 offspring.