The calico cat is a type of domestic cat that is a mixture of colors. Its coat is generally 25% to 75% white, and the patches of color can range from black, orange, or both. It can also have up to three additional colors. This pattern makes it a beautiful pet to own and is a very popular breed.
X chromosome
X-inactivation is a genetic phenomenon that occurs when the X chromosome is inactive in an embryo. This process is a natural process and occurs during embryonic development. The inactive X chromosome coils up into the Barr body, meaning that it cannot express its genes. The active X chromosome expresses genes that determine physical traits.
Y chromosome
A calico cat has two chromosomes – an orange and a black one. In a calico cat with a black chromosome, the cat will look like a black cat while an orange cat will have an orange chromosome. If the X-chromosome is inactive, the cat will not display a calico pattern. X-chromosomes are inactivated at different times in different cats.
XXY chromosome
The X chromosome carries the gene for fur colour. The calico cat has two different alleles of this gene – one allele gives the cat orange fur and the other allele gives the cat black fur. Both parents must pass on both alleles to produce a calico cat. The result is a cat with alternating black and orange patches. Calico cats also are known as tortoiseshell cats.
X-inactivation of chromosomes
In a calico cat, the X-chromosome is inactivated, a phenomenon that is common in female mammals. Although it is not clear exactly when this occurs, it usually occurs in an early stage of embryogenesis. Cats are born with one or more alleles of the orange gene. In some cases, X-inactivation is predetermined, but in other cases, it is random.
XXY combination
XXY cats have a pronounced orange and black coat, and are called calico cats. These cats are the result of a genetic variation known as lyonsation. The cat inherits one X chromosome from each parent and the remaining X chromosome comes from its father. It is extremely rare for male cats to have an extra X chromosome. Male calico cats may be sterile or may have a genetic anomaly.
Dilute calicos
Dilute calico cats are domestic cats with a tri-coloured coat. Their coat is a combination of cream, grey, and areas of white. The dilution gene is responsible for the muted colors. These cats exhibit the same behavior and appearance as their calico cousins.
XXY combination in males
A male calico cat has a pattern of fur that is predominantly white with patches of two different colors. This fur pattern is called a calico and is caused by a cat’s X chromosome. A male cat has only one X chromosome, unlike a female. This can occur in three ways: he may have one X chromosome or both, or he may have the XXY combination.
X-inactivation of chromosomes in females
The female calico cat has an X-inactivated chromosome. This mutation occurs rarely in male cats and is caused by a gene called XXY-complement. The X-chromosome inactivation produces a patchwork coat in calico cats. However, scientists are unclear of the exact mechanism that causes this mutation.
