![]() Many of these cats were photographed at the Richmond Animal Protection Society (RAPS) shelter, in Richmond BC. See the “Calico and tortoiseshell cats” gallery for examples of the wide range of colour patterns that X-inactivation can cause. But female cats can be black (BB), orange (OO) or black/orange (BO), in which case cells that have silenced the O-carrying X chromosome are black, while those silencing B are orange. Male cats, having only a single X chromosome, are either black or orange. This gene has two forms (alleles) – either black (B) or orange (O). We can see this mosaicism in cats because there is a gene for coat colour on the X chromosome. Once that choice is made, it is passed down through cell division, resulting in females being a mosaic mix of cells with either the maternal or the paternal X active. Inactivation occurs early in female development, and either X chromosome (the one inherited from the dad – paternal or the one inherited from mom – maternal) is chosen to be silenced. We study how this inactivation occurs, and then is maintained in all cells of a female – as is seen in a calico cat. This poses a ‘dosage’ problem as females now had twice the copy number as males – so the process of X-chromosome inactivation came to the rescue and silences most genes on one X in females. Long ago, these were a pair of chromosomes, and contained around 1000 genes, but as the Y chromosome became specialized for its role in sex-determination, it lost many of these genes. Mammalian females have 2 X chromosomes, while males have 1 X chromosome and the sex-determining Y chromosome. ![]() ![]() No – we don’t study cats– but a calico cat is a pretty example of X-chromosome inactivation. Torties, unfortunately, don’t have any other names/nicknames.Calico cats – ‘X’plained… Why c alico (and tortoiseshell) cats are the mascots of my lab Yes! Calicos are also called tri-colour cats or tortoiseshell with white. Are There Any Other Names for These Cats? Being a Calico owner, I can confirm that my cat shows signs of “Tortitude” or “Calico Attitude.” If you think that your cat has a particular attitude, you should definitely check out this article for a description of both. Do Calicos and Torties Share a Similar Personality?Īlthough not completely scientifically based, it is believed that both Torties and Calicos have a very particular personality. Nope! Calicos and Tortoiseshell cats can be almost any breed, including long haired! There are, however, some breeds that express these colourings more frequently than others. Even though the spot may be extremely small, doesn’t make your cat any less of a Calico! Are Calicos or Torties Always Short Hair? ![]() This can be as small as a cm spot on your cat’s body. Nope! Some Calicos only express very, very little white on them. (If you’re interested in why check out my post about it here.) Do All Calicos Have Big White Spots? While any cat can have white colouring, not ever cat can express both orange and black. These genes are called melanocytes and have a simple “on-off” function. The colours black and orange are carried in the X chromosomes, while the colour white is expressed from your cat’s genes. So Why Do Some Cats Have White Fur And Others Don’t? While Calicos share a similar colouring, being black and orange, they also have patches of white fur on them. Torties don’t always have dominant colouring and can be born with something called “dilute colouring” which simply means that the black and orange appear lighter on their fur. Tortoiseshell cats or Torties are commonly a mixture of black and orange. The only issue was… Kalista is not a tortoiseshell! It can be pretty hard to pin down what breed of cat you have, and although Tortoishell isn’t a breed, it can still sometimes be confusing what cats with this colouring are called. After we adopted Kalista a number of our friends congratulated us on our beautiful new Tortoiseshell Cat.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |