Description: Genetically-altered mutant mice created using transgenic and gene-targeting approaches may develop significant physical abnormalities as a result of their induced mutation. These abnormalities may be detectable through body weight and length, organ weight, physical examination, and/or blood serum chemistry. Significant differences in organ weight or serum chemistry of homozygous animals may indicate a pathology that has resulted from their induced mutation. The KOMP Phenotyping Pilot project will examine, necropsy, and compare 100 strains of homozygous knockouts and their wildtype littermates following behavioral testing. Selected tissues from each animal will be archived for future analysis.