Cream fur: a new mouse mutation that may cause unusual lipid metabolism

In 1986 an albino mouse with cream yellow coat color was discovered in a breeding colony of strain CAL20, which is an IgH-C congenic strain of BALB/c mice, supported by the Institute for Experimental Animals, Faculty of Medicine, Kanazawa University. Genetic analysis revealed that the cream yellow coat color phenotype was controlled by a single recessive mutant gene on chromosome 13. A preliminary study with biochemical and histologic examinations showed that cream yellow hair contained more fatty acid than unaffected normal hair and a large number of lipid droplets accumulated in parenchyma cells of the liver in mutant mice, as early as the age of 32 days old, suggesting that the cream yellow coat color was due to unusual lipid metabolism. The locus was designated cream fur locus and was given the gene symbol crf. In addition, it was found that recombination frequencies in the vicinity of the region of the crf locus were markedly different between male and female meiosis.