How is the color of cats inherited? - briefly
The color of cats is primarily determined by three genes: O (orange), B (brown/black), and D (dilute). The combination of these genes in various alleles dictates the final coat color and pattern, with dominant alleles often overriding recessive ones.
How is the color of cats inherited? - in detail
The inheritance of cat coat colors is a fascinating subject that involves complex genetic mechanisms. Cats have 38 chromosomes, with genes determining various aspects of their appearance, including coat color. The primary genes involved in feline coat color inheritance are O (Orange), B (Brown), and D (Dilute).
The O gene, located on the X chromosome, is responsible for producing the enzyme tyrosinase, which is essential for the synthesis of melanin. Melanin determines the base color of a cat's fur. Female cats have two X chromosomes and can be homozygous (OO) or heterozygous (Oo). A female cat with the OO genotype will have an orange coat, while a heterozygous female (Oo) may express either orange or non-orange colors depending on other genes. Male cats, having only one X chromosome, can either be orange (O) or not (o).
The B gene, also located on the X chromosome, affects the type of melanin produced. Cats with the BB genotype have a non-agouti pattern, displaying solid colors like black or brown. The bb genotype results in an agouti pattern, where individual hairs have alternating bands of color. This gene interacts closely with the O gene to produce various coat patterns and colors.
The D gene, found on chromosome 7, controls the dilution of melanin production. Cats with the dominant allele (DD or Dd) exhibit a full-color coat, while those with the recessive allele (dd) display a diluted color, such as cream instead of orange or gray instead of black. This gene modifies the expression of other genes, leading to a wide range of coat colors and patterns.
Additionally, there are modifier genes that influence the final appearance of the cat's fur. These include the A (Agouti) gene, which determines the distribution of pigment along the hair shaft, and the S (Spotting) gene, which affects the size and shape of white patches on the coat.
In conclusion, the inheritance of cat coat colors is governed by a combination of genes that interact in intricate ways to produce the diverse range of feline appearances we see today. Understanding these genetic mechanisms provides valuable insights into the biological processes that shape the physical traits of cats.