How are cat colors obtained? - briefly
Cat colors are primarily determined by two types of pigments: eumelanin and pheomelanin. These pigments are produced in specialized cells called melanocytes, which are influenced by genetic factors that dictate the amount and distribution of each pigment.
How are cat colors obtained? - in detail
Cat coloration is determined by the interplay of genetics, biochemistry, and developmental factors. The primary pigments responsible for coat colors in cats are eumelanin (black or brown) and pheomelanin (red or yellow). These pigments are produced by specialized cells called melanocytes, which are present in the hair follicles of the skin.
The color of a cat's fur is influenced by several genes that control the production and distribution of these pigments. One of the most significant genes is the agouti gene (A), which regulates the pattern of banded or non-banded colors on individual hairs. The dominant allele (A) results in banded patterns, such as the tabby coat, while the recessive allele (a) produces a solid color.
Another crucial gene is the melanocortin 1 receptor gene (MC1R), also known as the extension locus (E). This gene controls the length of the hair shaft that is pigmented. The dominant allele (E) allows for full-length pigmentation, resulting in a solid color or a pattern with long bands of color. In contrast, the recessive allele (e) restricts pigmentation to the tip and base of the hair, creating short bands and giving rise to patterns like ticking.
The amount and type of eumelanin produced are determined by the tyrosinase gene (T). The dominant allele (T) promotes the production of black eumelanin, while the recessive allele (t) leads to the formation of brown eumelanin. This gene is also responsible for the dilution effect seen in some cats, where the presence of a modifier gene can lighten the coat color.
Pheomelanin production is controlled by the agouti-related protein gene (ASIP). The dominant allele (A) inhibits pheomelanin synthesis, resulting in black or brown fur, while the recessive allele (a) allows for red or yellow fur. This gene is essential for the development of red or cream coat colors in cats.
In addition to these primary genes, modifier genes can influence the expression and distribution of pigments, leading to a wide variety of cat colors and patterns. For example, the inhibitor gene (I) can suppress the expression of certain pigments, resulting in color dilution. The piebald spotting gene (S) can restrict the migration of melanocytes during development, creating white spots or patches on the fur.
The final coat color and pattern are determined by the combined effects of these genes and their interactions with each other. This complex interplay results in the diverse array of cat colors and patterns observed today.