Basic Cat Genetics Devon Rex Coat Colour Inheritance Wisecracks Cattery

**SOME VERY BASIC COAT COLOUR GENETICS**
Each chromosome contains many thousands of genes. At times when the chromosomes multiply, a mistake occurs and the resulting gene is not an exact replica of its parent. These genes are referred to as ALLELES. Alleles of a gene are always at the same location on the chromosome as the original gene. In any given cat there can only be two copies of each gene, e.g.. one from each parent. However there may be more than two possible versions or alleles of each gene, e.g.. there are three different tabby genes, blotched, mackerel and ticked. Very basically genes can be Dominant (represented by an upper case letter), Recessive (represented by a lower case letter) or they can be of equal power to to speak and share their expression. The term GENOTYPE, refers to the genetic makeup of a cat, whereas the term PHENOTYPE refers to the appearance of the cat. If a cat has a copy of a dominant gene for any characteristic, they will show that trait, e.g.. a cat with a genotype Aa, will be a tabby (agouti), but will carry the gene for non tabby. For a cat to show a recessive trait they must have two copies of the recessive gene, e.g.. a cat with the genotype aa will be a solid colour ( no Tabby)

**SOME EXAMPLES OF DOMINANT & RECESSIVE TRAITS, (GENES) AND SYMBOLS**
Dominant Traits always represented by a capital letter	Possible Genotype	Recessive Traits always represented by a lower case letter	Possible Genotype
White Spotting S	S or Ss	No White Spotting s	ss
Agouti A Tabby	A or Aa	Non Agouti a Non Tabby	aa
Dense Coat Colour D Black or Chocolate	D or Dd	Dilute Coat Density d Blue or Lilac	dd
Melanin Inhibitor I Silver or Smoke I	I or Ii	Non Silver i	ii
Full Coat Colour C	Cc^s, Cc^b, Cc^a, Cc	Albino Alleles - c^sc^bc^a c For further explanation see Albino Alleles	Pointed Cats may be c^sc^s or c^sc^bor c^scc Sepia Cats may be c^bc^borc^bc^sor c^bc^a orc^bc Mink cats are c^bc^s Blue eyed White cats may be c^ac^aor c^ac red eyed white cats would be cc
Short Hair L	L or Ll	Long Hair l	ll
Manx M Semi Lethal MM kittens die in utero	M or Mm	Non Manx m	mm

Any of these recessive Traits can 'hide' and show up out of the blue. However when you are breeding cats, or know some of their history you can often figure out what they are carrying in the way of recessive genes.
If a cat showing any recessive trait is mated, all of their progeny will either show the recessive trait or carry a copy of it.
Two cats showing a recessive trait, when mated to one another cannot produce kittens showing the dominant expression of that trait, e.g.. two long haired cats cannot produce a short haired kitten.
With the dominant allele of any gene at least one parent must show it for any progeny to show it,e.g.. A Tabby crossed with a non Tabby may produce Tabbies, however two Non Tabbies cannot produce any Tabby kittens.

**RED & DOMINANT WHITE**
These two genes are unusual, in that their presence is able to mask or 'paint over' other colours, this is referred to as EPISTASIS.
Dominant White symbol W Because of this paint over effect, every Red or Cream or Pure White cat is actually another colour underneath. A pure white cat may be any colour or coat pattern under the White, including Red and Cream, Pointed, Burmese, Tonkinese etc. Dominant white is totally different from White Spotting. White Spotting is the typical cat with anything from a white bib right through to just a few spots of colour on an otherwise white cat.
Red symbol Xo (Sex Linked) Red cats are Black or Chocolate, Cream are Blue or Lilac. The Red gene does not cover coat pattern, e.g. Pointing, Burmese, Tonkinese, Bicolour, Tabby. In other words, the cat actually has the genes for these colours but they are unable to be expressed (show). Red also affect the Agouti (Tabby) genes, in that it allows the tabby pattern to show even on cats that are Non Tabby. The Red gene is sex linked, it only occurs on the X chromosome, not the Y chromosome. Therefore if a male cat (XY) receives an X chromosome from his Mother with the Red gene on it, he will be red or cream. Because a female has two X chromosomes (XX) they may receive either one or two X chromosomes containing the Red gene. If they receive one red X, they will be Tortoiseshell, if they receive two red X chromosomes they will be red or cream. Tortoiseshell males only occur in male cats who have abnormal chromosomes, e.g.. XXY See the mating chart below

Table Of Red Cat Matings
Mating	Red Males	Non Red Males	Red Females	Toroiseshell Females	Non Red Females
Red Male x Non Red Female	No	Yes	No	Yes	No
Red Male x Toroiseshell Female	Yes	Yes	Yes	Yes	No
Red Male x Red Female	Yes	No	Yes	No	No
Non Red Male x Tortoiseshell Female	Yes	Yes	No	Yes	Yes
Non Red Male x Red Female	Yes	No	No	Yes	No
Non Red Male x Non Red Female	No	Yes	No	No	Yes

**WHITE SPOTTING (S) GENE**
White Spotting as just mentioned is the gene responsible for your typical bicolour cat. The White Spotting gene is dominant. This gene has what we call Variable Expression, as you can see from the many varied Bicolour patterns you see in the cat population, from mere smudges of white, through to all white with smudges of colour When a cat has both White Spotting genes i.e. SS, they will have a greater proportion of white than those with only one of the genes i.e. Ss. The White Spotting gene also affects other genes. Tortoiseshell cats with white on their bodies will have large patches of colour, as opposed to those without any white where the colours are all mixed. White Spotting also affect the Pointing and Burmese genes. Again when there is white on the body of the cat, the coloured parts of the body will become almost as dark as the mask and tail.

**AGOUTI GENE (A) ALLOWS TABBY COAT PATTERN TO BE EXPRESSED (TO SHOW)**
There are three Tabby Alleles, in order from dominant through to recessive these are Ticked Tabby, symbol t^b as seen in abyssinians Mackerel, symbol T, striped Blotched, symbol t, butterfly blotches. All cats have the genes for a tabby coat pattern. Whether they show their tabby markings or not is dependent on the presence of the Agouti gene (A) will be Tabby, Non Agouti (aa) will be non Tabby or solid colour. As mentioned under the red gene, if the red gene is present it allows the tabby pattern to show even in a non agouti cat. Some high grade smoke cats may also show a ghost tabby pattern, especially while they are young. Because Ticked is not completely dominant over Mackerel, many ticked tabbies will still have stripes on their tails and legs.

**THE ALBINO COAT COLOUR IN CATS**
The alleles for coat colour are represented by B for Black or b for Chocolate.
The alleles for coat colour density are represented by D for dark (dense Black or Chocolate) and d for dilute (Blue or Lilac)
Albino Genes Responsible For Pointing, Burmese (Sepia)andTonkinese (Mink) Coat Patterns Burmese also known as Sepia and Tonkinese also known as Mink are terms which refer both to a particular breed of cat and to a particular coat pattern in any breed of cats. Whereas Pointing is used to describe the coat pattern seen in the Siamese, Birman etc. Kittens born with these coat pattern, are born white through to a light coffee colour and develop their colours slowly over the first months of life. The first photo shows Oscar at 2 days coffee coloured kitten in foreground, the second at 10 weeks. The last photo shows Oscar in foreground still growing an adult coat, Monica in background is the same colour but with her adult coat!	The Dominant form of this gene is C or full coat colour. The Albino Alleles in order from dominant through to recessive are Full Coat Colour, symbol C Pointing, symbol c^s Burmese, symbol c^b Blue eyed White symbol c^a Red eyed white symbol c Because c^b oror c^s are of 'equal power when a cat has a copy of each the genes share expression these cats are Tonkinese (Mink cbcs⁾ The Pointing and Burmese genes change Black to Seal, other colours remain unchanged. Pointing and Burmese (Sepia) genes are affected by the White Spotting gene (see White Spotting)
	You Can Also Check Out Wisecracks Cilla Consealer changing from her newborn colourless state to her adult colouring here

**SILVERS TABBIES & SMOKE**
**Action of the Inhibitor Gene symbol I**
The Inhibitor gene is responsible for Smoke and Silver Tabbies. The gene literally inhibits the formation of colour at the base of the hair. The higher the grade (or expression) of this gene the further up the hair shaft the colour is inhibited. A tabby cat with this gene is referred to as a Silver Tabby, the most extreme of the expression being seen in the Chinchilla coat, these cats are actually very high grade Black Silver Tabbies. A non tabby cat with the same gene will be referred to as a Smoke. The Inhibitor gene in devons can actually change the colour of the cat significantly as they move from their juvenile suede coat to their adult coat. When they are sporting their suede coat the kittens or young cats may almost look pointed, with the shortest of their coats being very light, while their face, legs ears and tail are their adult darker colour.

TABLE OF CAT COAT COLOURS - POSSIBLE MATINGS
Mating	Black	Blue	Chocolate	Lilac	Kitten Carry
Blue x Blue B-dd x B-dd	No	Yes	No	If both parents carry chocolate
Blue x Chocolate B-dd x bbD-	Yes	If chocolate parent carries dilute	If blue parent carries chocolate	If chocolate parent carries dilute and blue parent carries chocolate	All kitten will carry blue
Blue x Black B-bb x B-D-	Yes	If black parent carries dilute	If both parents carry chocolate	If black parents carries dilute and chocolate and blue parent carries chocolate	All kittens carry blue
Blue x Lilac B-dd x bbdd	No	Yes	If blue parent carries chocolate	If blue parent carries chocolate	All kittens carry blue & chocolate
Black x Chocolate B-D- x bbD-	Yes	If both parents carry dilute	If black parent carries chocolate	If black parent carries chocolate and blue and chocolate parent carries dilute	All kittens carry chocolate
Black x Black B-D- x B-D-	Yes	If both parents carry dilute	If both parents carry chocolate	If both parents carry dilute and chocolate	.
Black x Lilac B-D- x bbdd	Yes	If black parents carries dilute	If black parent carries chocolate	If black parent carries dilute and chocolate	All kittens carry dilute and chocolate
Chocolate x Chocolate bbD- x bbD-	No	No	Yes	If both parents carry dilute	All kittens carry chocolate
Chocolate x Lilac bbD- x bbdd	No	If chocolate parent carries dilute	Yes	If chocolate parent carries dilute	All kittens carry chocolate and dilute
Lilac x Lilac bbdd x bbdd	No	No	No	Yes all kittens will be Lilac	All kittens carry chocolate and dilute

- indicates carried allele unknown

Red symbol Xo (Sex Linked)

Albino Genes Responsible For Pointing, Burmese (Sepia)andTonkinese (Mink) Coat Patterns