Why does a white cat appear? - briefly
The appearance of a white cat is primarily due to genetics. Specifically, it is the result of a recessive gene that inhibits the production of melanin, which is responsible for coat color in cats.
Why does a white cat appear? - in detail
The appearance of a white cat is determined by genetics, specifically the inheritance of particular alleles that control coat color. There are two main genes responsible for this trait: the C (for color) gene and the S (for spotting) gene.
The C gene controls the production of melanin, the pigment that gives cats their fur color. There are two primary alleles at this locus: C (dominant) which produces black or brown fur, and c (recessive) which results in a diluted color like gray or cream. A cat with two recessive c alleles (cc) will have a very light-colored coat.
The S gene affects the distribution of pigment on the fur. The dominant S allele causes spots, while the recessive s allele allows for solid colors. When combined with the homozygous recessive cc genotype at the C locus, the ss genotype results in a completely white cat.
For a cat to be entirely white, it must inherit two copies of the recessive c allele from the C gene and two copies of the recessive s allele from the S gene (ccss). This genetic combination is necessary for the absence of melanin production and the solid distribution of what little pigment is present, leading to a pure white coat.
Additionally, the KIT gene plays a role in regulating the development and migration of melanocytes, the cells that produce melanin. Mutations in this gene can also lead to a lack of pigmentation, resulting in a white cat.
In summary, the appearance of a white cat is the result of specific genetic combinations involving the C (color) gene and the S (spotting) gene, with the KIT gene potentially contributing as well. Understanding these genetic factors provides insight into the mechanisms that determine coat color in cats.