Cat Colour Genetics

There are so many different colours and patterns to be found on a cat's coat that it can be difficult to choose when adopting or buying one. Have you ever wondered how the pattern and colour is decided whilst the kitten is growing in the uterus? We have all seen litters where there are several kittens all with different colours and markings or litters where all the kittens are the same more or less. Firstly it may be good to establish what the commonest colours and patterns are. Tabbies are striped like tiger's and have thin lines of colour on their faces together with a tabby 'M' on the forehead. The tabby pattern is thought to come from the ancestors of domestic cats and indeed the only true wild cat left in the British Isles is the Wild Cat of Scotland which is, of course, striped. Within the tabby range there are numerous patterns and colours such as brown, red, blue, cream and silver.Next there are the solid colours and Smokes which are the same colour, more or less, all over and come in black, blue (grey), or white. It is thought that solid coloured cats are the result of a gene that suppresses the tabby pattern so it is possible that you may find shadowy stripes in the coat of your solid colour cat should you look closely. However the tabby suppressing gene is ineffective on red or cream cats so they will always have tabby markings. A solid white cat is the result of a totally different gene that completely suppresses colour. Any cat can have some white markings amongst their all over colour and these are often referred to as 'white paws' or 'white markings'. Black and white cats meanwhile are sometimes informally called 'tuxedo' which immediately conjures up the type of markings it has. By the way, ''red is used in the cat world to describe the colour we may call marmalade or ginger, whilst 'blue' is used to describe a cat that we would call grey.Then there are the Torties, Calicos and points - we could go on and on but just what is it that produces these colours and are any of them more dominant than others? Why is it that the kittens in a litter can all be different colours?The answer to the second question appears to be easy (it isn't but we are trying to keep this simple) a female cat may mate with many different males when she is in season and, as each egg is fertilised separately, each kitten can theoretically have a different father. The first question is a bit more difficult to answer and we now have to look at genetics even though the subject as a whole is very specialised and complex.The proto melanin producing cells in the embryo kitten is controlled by two genes but by the time they reach the skin they are also affected by additional genes. The interaction of the genes is not fully understood and genetics is a science in itself so, assuming you are not reading this article in preparation for your degree, we will look for less complex explanations.Male kittens obtain both colour genes from their mother so the males of a litter will always be either the same colour as their mother or a different shade of their mother's fur. If the dam is multi coloured then just one of her shades may be passed on to her son. Female kittens have a colour gene from each parent so the female kittens in a litter will always be a combination of their mum and dad's colours although shades may vary.If a female cat is red (orange), or cream coloured, her father must have also been red or cream whilst her mother would have some red or cream on her somewhere. In cat genetics it is only the immediate parents that affect coat colour so there is no chance of two tabbies producing a ginger cat and in pedigree cat's colour cannot be absolutely guaranteed except in colourpoints like Siamese. Dominant colours cannot skip generations so a black cat must have had at least a partially black mum or dad. Likewise a cream coloured cat mating with a blue (grey) cannot produce a black kitten and two colourpoint cats cannot have any offspring that are not colourpoint although two cats that do not appear to be colourpoint can have colourpoint kittens as they may be carrying the gene. If a colourpoint cat mates with a cat without the colourpoint gene then the kittens will not be colourpoints. Parti coloured cats such as Torties are almost always female although there are exceptions and two longhair parents cannot have a shorthair kitten whilst a kitten's pattern can be inherited from either parent. I recently visited my local animal shelter where kitten season is in full swing and I saw a beautiful pale ginger queen with a litter of tiny replicas of herself. Why were they all ginger? What colour can the father have been? Were they all the same colour because they all had the same father? Looking at the easy to understand version of genetics I believe that the father of the female kittens in the litter must have had some red in his coat whilst the males could have had a father with any coat colour as they take on the colour of their mother. (Didn't really matter as they were all gorgeous!) All information in this article is very much in layman's terms and does not attempt to educate with any seriousness the very complex study of genetics and reproduction. However, if you are interested in cats and kittens then it is certainly a fascinating subject and maybe you will be inspired to find out all you can. Certainly if you are thinking about breeding cats then you will need to have some knowledge and hopefully this article will have given you a small start.