Why does my cat have brown eyes? - briefly
The color of a cat's eyes is largely determined by genetics. Brown eyes are one of the most common eye colors in cats, resulting from the presence of melanin in the iris.
Why does my cat have brown eyes? - in detail
The color of your cat's eyes is determined by several factors, including genetics and the presence or absence of certain pigments.
Cats are born with blue eyes due to the lack of melanin, which is responsible for eye color in most mammals. Melanin is a pigment produced by cells called melanocytes, and it can be found in various shades from black to brown. As kittens grow older, the enzyme tyrosinase activates the production of melanin, causing the eyes to change color.
The most common eye color in cats is green or yellow-green, which results from the presence of lipofuscin, a brownish pigment that accumulates with age. However, brown eyes are also relatively common and can be attributed to two primary factors: the amount and distribution of melanin, and the presence of specific genes.
Firstly, the concentration and pattern of melanin in the iris play a significant role in determining eye color. In cats with brown eyes, the melanocytes produce more melanin, which is distributed evenly throughout the iris. This results in a darker hue compared to cats with green or yellow-green eyes, where the melanin is typically concentrated in the periphery of the iris.
Secondly, genetics also influence eye color in cats. The gene responsible for eye color in cats is located on chromosome 5 and has been identified as OCA2 (Oculocutaneous Albinism Type 2). This gene controls the production and distribution of melanin in the iris. There are different variations or alleles of this gene, which can lead to various eye colors. For example, the dominant allele (B) results in brown eyes, while the recessive allele (b) leads to blue eyes.
In summary, your cat's brown eyes are a result of the combined effects of genetics and the production and distribution of melanin in the iris. The OCA2 gene on chromosome 5 controls this process, and the dominant allele (B) is responsible for the brown eye color in your feline companion.