Basic Genetics: Coat colours with red

Gene O, o

ORANGE gene O

Gene O is responsible that a black, chocolate or cinnamon coloured coat gets red. This gene colours alls hairs to red.
It is dominant over its companion o.
But gene O has a speciality, it is sex linked to the chromosome X. You remember, a male has the chromosome pair XY, a female has XX. Therefore, as gene O is linked to the X-chromosome, a red male has the gene pair OY and only passes once gene O to his litter, a red female has the gene pair OO and can pass twice gene O to her litter.

Non-orange gene o

Consequently a male which has the gene pair oY has a black coat, a female which has the gene pair Oo is a tortie.
A female which has the gene pair oo is of course black.

"dark" colour diluted colour
red cream
black tortie blue tortie
chocolate tortie lilac tortie
cinnamon tortie fawn tortie

Possible gene combinations

OY red male Note that a red male can only pass once the gene O for red coat colour to his offsprings, while a red female can pass twice the gene O. If the second gene Y from a red male is passed to his offsprings, these will all be boys.
OO red female
Oo tortie female

 

Colours with red

Now - only with 3 genes - we know already the genetic fingerprints of a lot of colours.

non diluted colour gene combination diluted coat colour gene combination
red male BB DD OY female BB DD OO cream male BB dd OY female BB dd OO
BB Dd OY BB Dd OO
Bb DD OY Bb DD OO Bb dd OY Bb dd OO
Bb Dd OY Bb Dd OO
Bbl DD OY Bbl DD OO Bbl dd OY Bbl dd OO
Bbl Dd OY Bbl Dd OO
black tortie female BB DD Oo blue tortie female BB dd Oo
BB Dd Oo
Bb DD Oo Bb dd Oo
Bb Dd Oo
Bbl DD Oo Bbc dd Oo
Bbl Dd Oo
chocolate tortie female bb DD Oo lilac tortie female bb dd Oo
bb Dd Oo
bbl DD Oo bbl dd Oo
bbl Dd Oo
cinnamon tortie female blbl DD Oo fawn tortie female blbl dd Oo
blbl Dd Oo

 

My red cat has so many stripes

Is there any difference between a red and a red tabby ?
Particularly not. Red and red tabby cats are genetically the same. Red self is the result of selective breeding. There are taken the red tabbies - mostly blotched - which show very little pattern to breed Red selves. The more often this procedure is repeated the more the pattern will get diffuser so that in the end the tabby pattern cannot be seen. You can see on the Red selves that they are tabbies if you look at their face, where they show the "M" on the front, you will also find mostly the most upper ring on the front legs present.
Selective breeding is also necessary to avoid the white locket on the throat and the white patch on the tail tip. The older the cats are the larger is usually the white patch on their tail tip.
From the phenotype you cannot see if your Red tabby is an Agouti tabby or not, because the Agouti gene which turns "black" hairs into yellow banded hairs cannot fully operate on orange hairs. We will discuss this fact in a later lesson when we are coming to the Agouti gene.

All cats which are not red carry the gene combination oo

coat colour gene combination coat colour gene combination remarks
black B- D- oo blue B- dd oo Note: For "B-" you might put BB, Bb or Bbl.
For "D-" you might put DD or Dd.
The "-" indicates that we cannot say for sure which gene is present.
chocolate b- D- oo lilac b- dd oo Note: For "b-" you might put either bb or bbl.
cinnamon blbl D- oo fawn blbl dd oo -
As "oo" is present by default on all non-orange cats we will omit this gene pair in future which does not mean that it is not present. We do this only because of readability.

 

How can this theoretical knowledge be used for the breeding practice ?

Example 1:
Imagine the following gene combinations:

All these cats - females - are red or cream, if they have dd. At the gene O you can see the meaning of Mimic gene, another mimic gene is the gene W responsible for an overall white coat colour. If you want to find out if your cat carries black, chocolate or cinnamon you must have a closer look on the pedigree or do a test mating with your cat. For example if you want to know if your cat carries chocolate you have to mate her with a chocolate male.

You want to breed a red female.

Example 2: We cross a red male with a black female
Our male has the gene combination: BB D- OY
Our female has the gene combination: BB D- oo

  male
BDO BDY B-O B-Y
female BDo BB DD Oo
black tortie females
BB DD oY
black males
BB D- Oo
black tortie females
BB D- oY
black males
B-o BB D- Oo
black tortie females
BB D- oY
black males
BB -- Oo
black or blue tortie females
BB -- oY
black or blue males


With these cats we will never produce red females. We will also not get red males. We will only get tortie girls.

Example 3:
We change the colours between the male and the female. We cross a black male with a red female
Our male has the gene combination: BB D- oY
Our female has the gene combination: BB D- OO

  male
BDo B-o BDY B-Y
female BDO BB DD Oo
black tortie females
BB D- Oo
black tortie females
BB DD OY
red males
BB D- OY
red males
B-O BB D- Oo
black tortie females
BB -- Oo
black or blue tortie females
BB D- OY
red males
BB -- OY
red or cream males


With this combination we only get red/cream males and tortie females, we still don't get red females.
You will also not get a red female, if you use a tortie female. You can try it.

Example 4: We cross a red male with a black tortie female
Our male has the gene combination: BB D- OY
Our female has the gene combination: BB D- Oo

  male
BDO BDY B-o B-Y
female BDO BB DD OO
hurra !
red females
BB DD OY
red males
BB D- Oo
black tortie females
BB D- OY
red males
BDo BB DD Oo
black tortie females
BB DD oY
black males
BB D- oo
black females
BB D- oY
black males
B-O BB D- OO
once more
red females
BB D- OY
red males
BB -- Oo
black or blue tortie females
BB -- OY
red or cream males
B-o BB D- Oo
black tortie females
BB D- oY
black males
BB -- oo
black or blue females
BB -- oY
black or blue males


You will get red females only when both parents have red, that means at least the female must be a tortie which is crossed with a red male. Of course you'll get red females when both parents are red.


� European Cat Fancy 1997-1999. Please respect the Copyright. Please contact us at [email protected].
Last modified on  99-01-16

Hosted by www.Geocities.ws

1