Have you ever wonder where the colour comes from in out feline friends. It’s alway fascinated me especially since fostering and you can get such a variety of colour combinations in one litter.
Most mammals have similar gene patterns for the purposes of colour. You may have noticed that most all mammals come in shades of gold, brown, black and white.
Here we’ll look into why that is and what causes it in our dear feline friends. Reference links will be provided at the bottom of the article so that you may delve further into the world of colour genetics at your leisure.
Breed
Russian Blue
When dealing with breed colouration, we must consider where the breed started. The Russian Blue cat, for instance, spent a very long time removing white and brown from the gene pool of its breed.
Though there may still be a kitten that pops up with unique colouring now and then, they are relatively rare.
However, colouring and pattern are often confused. Take the Birman for instance.
This breed has two specific genetic modifiers that make it appear as it does, one so breeds specific that it is called the Birman gene. When interbred, all Birman cats should have little white paws. This is the result of the Birman gene at work, placing a white blanket over each paw rather than allowing the natural colour to seep through.
So what’s the difference between pattern and colouring genetics? To take the Birman again, the cat with white paws could, genetically, still have lavender or black paws. The paw blanketing gene, instead, is hiding that with white. In mammals, white is not a colour. It is the absence of pigment. Therefore, this is a patterning gene instead. Since Birman cats can be any colour under the sun, most of their genetics revolve around patterning genes.
Birman Kittens
In dealing with the Russian Blue, it is a black cat that has been diluted through careful breeding. So is this a colour gene or a pattern gene? It is a colour gene. The modifier has been applied not to hide the colour, but to change the tone of it. Therefore, these dilute black cats are blue due to colour gene interference.
Gendered Colours
Gender may play a part in feline colouration as well. Sexual dimorphic colours are not unheard of in much of the animal world. Though they do not fall into the category of mammals, peacocks are an excellent example. Females are rarely of the same brilliant plumage as their male counterparts. And why? Because these animals need to be able to hide their young as they nest, and females do the majority of nesting.
Within cats, the most common sexually dimorphic colours are orange and tortoise shell. Nearly everyone is aware that it is a rare female cat who is orange. It is an even rare male cat who is tortoise shell coloured and patterned. Again, we see the interference of pattern genes vs. colour genes. Unfortunately, a tortoise shell cat may be either. Without seeing the particular cat, it is impossible to tell. It is all in the colour of the eyes.
So why are most orange cats male? This has to do with chromosomes passed from mother to son. A male orange cat only needs one set of orange genetics to become orange. The female orange cat, on the other hand, also requires that her father passes along the orange trait. Since, outside of specific breeding attempts to make orange females, it is rare for this to happen most females from orange litters end up picking up pattern or colours from their fathers instead. This is why so many litters with orange boys have tabby, calico and tortoise shell girls. These girls carry orange but are patterned or coloured over with another shade.
To create orange females, one of the most popular breedings is in fact, genetically orange male to genetically orange female. This gives the highest chance that the kittens produced from the litter will be orange rather than blanketed by patterns or other colours. Though this is no guarantee- a cat whom is orange may produce all black kittens for the breeder who has not done thorough research into their cats’ backgrounds.
Chimeras Kittens
What has been said above holds true for all felines except for the strange and incredibly rare Chimera kitten.
Before we delve into Chimeras, we must note that it is ideal for these kittens to be neutered- as should all kittens be who are not used in responsible breeding programs.
Why is it so important for the Chimera? Most of them are infertile, to begin with, but these precious felines may fine themselves at the short end of the genetics lottery with regard to health. It is always better to be safe than sorry.
Chimeras are genetically two different animals that merged in the uterus to become one without added heads, limbs or other issues. So how does this happen? These cats tend to merge as eggs within their mother, very early in fertilisation. More often than not, one kitten is male, and another is female.
This again leads us to see issues with reproduction in the chimera, known or unknown. Females with high testosterone do not produce well, the same as males with high oestrogen. Cancer of the reproductive organs is pretty common with these cats. Some chimeras may even need hormone therapy, which is much easier to regulate when dealing with an altered pet.
On the other hand, chimera cats are some of the most colourful of all. Blue and brilliant orange tabbies, lilac and black striped cats, and all the pretty colours you can imagine run through chimera cats.
The only way to confirm a chimera is by testing the cat’s blood, though most researchers are happy to do this for a low cost. Since chimeras inherit both XX and XY genes, making them genetically both male and female, it is easy to see whether they are or are not chimeras in a laboratory setting. If you suspect your kitten or cat is a chimera, it is well worth testing.
- http://cfa.org/Breeders/CatColorsGenetics/BasicFelineGenetics.aspx
- http://www.fanciers.com/other-faqs/color-genetics.html
- http://www.vgl.ucdavis.edu/services/coatcolorcat.php
- http://www.catster.com/lifestyle/cat-genes-science-fur-color
- http://messybeast.com/mosaicism6.htm