calico cats and tortoiseshell cats are female

Their mottled coats are as a result of what genetics call Lyonization. Tortoiseshell Cats, often called “torties” for short, have a combination of two colors, normally black and orange displaying in a patchwork or mosaic. So, how can you spot the difference between a calico cat and a tortoiseshell cat? Read on! Tortoiseshell Cats To the untrained eye, these gorgeous mosaic-furred felines can be easily confused for one another. So a domestic shorthair cat can be a tortoiseshell just as much as a Japanese Bobtail can be a calico cat! This mutation exists in humans too, and it's called Klinefelter syndrome.Calico and tortoiseshell cats are best known for their beautiful multicolored coats of black, orange and white - and their “ tortitude ”.īoth “calico” and “tortoiseshell” are terms that refer to the color and pattern of a cat’s coat and do not actually refer to the cat’s breed. This is a chromosomal mutation known as XX male syndrome. If a male cat is calico (or tortoiseshell), this means that it has two X chromosomes and an Y chromosome. They can therefore only carry one variant of the orange gene in all their cells. Male cats, therefore, cannot be calico, since they only have one X chromosome. If they have the white patches, then these are a result of the white spotting gene, as explained in this article. The third color of a calico is a product of a completely separate gene. This is why some patches on the coat will be orange and some will be black. The cells in which the first X chromosome is silenced will express only the non-orange gene, and therefore produce the black (or brown) pigment, and the other cells will produce the orange pigment. If a female cat is a heterozygote for the orange gene (Oo), it will carry the orange allele (O) on one X chromosome and the non-orange allele (o) on the other X chromosome.

This means that in some cells one X chromosome will be silenced and in the other cells the other one. One of these chromosomes will be silenced in all of the cells by a random chance. The orange allele O codes for the orange pigment “phaeomelanin”, and the non-orange o for the black/brown pigment “eumelanin”.įemale cats carry two copies of the X chromosomes in their cells. This is the gene for the orange color (O/o) and it comes in two variants (alleles) – the orange (O) and the non-orange (o). The gene which determines whether the coat will be orange or black (or one of the diluted colors) lie on the X chromosome. Thus, all calico cats are also tortoiseshell, but not all tortoiseshell cats are calico. A similar coat pattern is tortoiseshell, where there is a lot less white in the fur, and the colored patches are mottled. There is usually a significant amount of white in their coat, and the red and black patches form patchwork. Genetics behind calico coat patternĬalico, or tricolor coat pattern, is the pattern of white fur with patches of two different colors, most commonly orange and black (or their diluted forms: cream, ginger, red and blue, tabby, gray). Female cats carry two copies of X chromosomes in each cell (XX), while males have an X and an Y chromosome (XY). The 19th pair of chromosomes are sex chromosome X and Y. This means that all the alleles (variants of genes) on each chromosome will also be in two copies (one on one chromosome and the other on the homologous chromosome).

Each chromosome, therefore, comes in two copies. For comparison, humans have 23 pairs of chromosomes in each cell, whereas, dogs, have a whooping number of 39 pairs. Background informationĬats have a 19 pairs of chromosomes in each cell, which totals in 38 chromosomes.

Learn more about this interesting phenomenon with Basepaws. Have you ever wondered why most calico cats are female? Well, it’s all about the power of genetics! This is also true for a similar coat pattern called tortoiseshell.

Calico cats and tortoiseshell cats are female