Originally inbred at the Rockefeller Institute, AKR mice are widely used in cancer research for their high leukemia incidence (60-90%) and in immunology as a source of the Thy1.1 (theta AKR) antigen. AKR/J mice are viremic from birth, and express the ecotropic retrovirus AKV in all tissues. The hair interior defect (hid) mutation, a strain characteristic of AKR mice, causes alterations in hair development that is only evident microscopically. Adrenocortical lipid depletion (ald) in AKR mice is caused by a mutation in sterol O-acyltransferase 1 (Soat1), and leads to a truncated SOAT1 protein. AKR/J mice are relatively resistant to aortic lesion formation on a semi-synthetic high fat diet and are hyporesponsive to diets containing high levels of fat and cholesterol.