THE GENOMIC ANALYSIS OF KIT IN WHITE SPOTTED CATS: CHARACTERIZATION OF THE BIRMAN GLOVES PHENOTYPE

Knowledge of the cats’ coat colors variants is important to enhance the understanding of mammalian physiology, development pathways, cancer predisposition, evolution and even forensic identification. The continued understanding would allow new opportunities in the prevention and treatment of skin diseases and discover the pathological basis of various forms of hereditary deafness. Moreover the development of a genetic test, hence a chance to identify the causative alleles for white spotting, would be helpful for cat breeders as a powerful tool to select and screen between different color genes. The aim of this study has been to find the gene that controls the different white spotting patterns in the domestic cat. The v-Kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) gene has been characterized has the best candidate gene that defines the different white spotting phenotypes. Regions of the skin, and corresponding hair follicles, lacking melanocytes are devoid of coloration and appear white in many species of mammals. Many patterns of the white phenotype exist across animal species; form dominat white to piebald to minimal bellyspots. From our previous study, KIT was found within the linked region for white spotting in cats. Four additional feline-derived markers were genotyped in a large pedigree of cats that segregates for ventral white spotting and complete linkage with KIT was detected. In this study, the KIT gene from random and pure bred domestic cats with various white spotting phenotypes was directly sequenced in order to identify DNA variants associated with the different patterns. A novel allele for the white pattern of the Birman cat breed, defined as symmetrical gloves ending with an even linea cross the front paws and white socks tapering up the back leg, was identified. Allele specific PCR was used to genotype candidate SNPs in a larger sample set including over 200 Birmans and over 900 additional cats comprised of twenty-one breeds, Birmans outcrosses and random bred cats. All the analyzed and verified Birman cats were homozygous for the “gloving” haplotype, suggesting that the phenotype is a result of the identified mutations and that this haplotype could be considered a breed unifying characteristic.