by L.C.

Created on: March 07, 2009

Few cats have coats that are as varied or beautiful as that of the Tortoiseshell cat (colloquially known as Torties). It should be noted that Tortoiseshell cats are not a breed of cats; rather, the name describes a very distinct colouring that all members of the category share, though most cat lovers will agree that Torties have certain personality traits that can group them together as well. Their signature blend of colours, which brings to mind a canvas with different shades of paint splashed onto it, can be attributed purely to genetics.

A quick biology lesson is in order to fully comprehend how a Tortie's coat is created. Tortoiseshell cats often have ginger patches, which are caused by the O gene. This shade can closely resemble yellow, orange or red, depending on the cat. The O gene is carried over by the X chromosome, and while a male cat generally has an XY genetic makeup, that of females is an XX makeup. If a female inherits one O gene, she will be a Tortoiseshell; two O genes, and she is a ginger cat.

However, what distinguishes Torties far more than their ginger fur is the fact that the different colours seem to be either patched or mixed together. This is because of X-chromosome activation, where certain cells will activate the O gene, and others will not. Their skin will therefore have patches where, in some places, the O gene has been activated, making it so that the fur is ginger, while in other spots the O gene is not activated and the fur is black.

This explains why Torties are most often femalemales only receive one X chromosome, so this gene is activated in all of the skin cells, since the Y chromosome does not have a feature that can activate or de-activate the O gene.

Naturally, not all Torties are black and red. Many have white patches in their fur, and this is caused by the semi-dominant piebald spotting gene. This gene will affect the embryo cells of the cat, and turn them into cells that produce skin. These cells have one main job: to cover as much of the kitten's skin as possible. Where the gene does not touch during skin formation (most often paws, stomach, chest, chin and back, areas that take the longest to reach), the fur will be white, because there are no pigment-producing cells.

Tortoiseshell cats have very particular personality traits that many describe as "Tortitude." While all cats are different, Torties tend to share in common the fact that they are very impish and curious. These cats are often also playful and entertaining,

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