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Gene A: Agouti

 
Eurocatfancy
Genetic terms in cats
Genome of the cat
Dominance of genes
Cat Breeding techniques
Crossing Table 1
Crossing Table 2
Crossing Table 3
Gene A: Agouti
Gene B: Black
Gene C: Full colour
Gene D: Diluted
Gene Dm: Dilute modifier
Gene Fd: Folded ears
Gene I: Inhibitor
Gene L: Shorthair
Gene Mc: Mackerel
Gene O: Orange
Gene S: Piebald spotting
Gene W: White
Gene XY: Sex
Quality Points for Cats

 

Gene A: Agouti

 

AGOUTI gene A

Gene A is responsible that each hair gets yellow banded.
In all tabby varieties - except the red tabby - gene A is necessary that the underlying tabby pattern which is present in each cat gets visible to you.
You find this gene also in the silver tabbies, in the goldens and colourpoint tabbies.

yellow agouti-banding

an agouti hair with the yellow banding

Non-Agouti gene a

Gene a is recessive to gene A. If a cat carries gene a double (aa) then its coat colour gets solid und you cannot see the underlying tabby pattern which is present in each cat.
Gene a is called to mask the tabby pattern.
When you look on new born kittens, f.e. black kittens, in the first days you can see the underlying tabby pattern. These tabby stripes dissappear when the kitten is growing, if it does not carry gene A, but carries aa.

Gene combinations

AA homozygous agouti
the tabby pattern gets visible
Aa heterozygous agouti
the tabby pattern gets visible
aa homozygous non-agouti
coat colour gets solid, the tabby pattern cannot be seen

 

How does gene A operate on the various colours ?

Non-diluted colours

Diluted colours

colour gene combination colour gene combination colour gene combination colour gene combination
black aa B- D- oo black tabby A- B- D- oo blue aa B- dd oo blue tabby A- B- dd oo
Gene A must be present only once to see the tabby pattern already. For "A-" you may put AA or Aa. For "B-" you may put BB, Bb, Bbl.
For "D-" you may put DD or Dd.
chocolate aa b- D- oo chocolate tabby A- b- D- oo lilac aa b- dd oo lilac tabby A- b- dd oo
For "b-" you may put bb or bbl.  
cinnamon aa blbl D- oo cinnamon tabby A- blbl D- oo fawn aa blbl dd oo fawn tabby A- blbl dd oo
red self male:
aa -- D- OY
or
A- -- D- OY

female:
aa -- D- OO
or
A- -- D- OO

red tabby male:
aa -- D- OY
or
A- -- D- OY

female:
aa -- D- OO
or
A- -- D- OO

cream male:
aa -- dd OY
or
A- -- dd OY

female:
aa -- dd OO
or
A- -- dd OO

cream tabby male:
aa -- dd OY
or
A- -- dd OY

female:
aa -- dd OO
or
A- -- dd OO

For "--" you may put BB, Bb, Bbl or bb, bbl or blbl. Remember that gene O colours all hairs to red regardless their colour. Remember also that between a red self and a red tabby is no difference.
black tortie aa B- D- Oo black tortie tabby A- B- D- Oo blue tortie aa B- dd Oo blue tortie tabby A- B- dd Oo
Note that all torties are females. Tortie tabbies are often called torbies.
chocolate tortie aa b- D- Oo chocolate tortie tabby A- b- D- Oo lilac tortie aa b- dd Oo lilac tortie tabby A- b- dd Oo
cinnamon tortie aa blbl D- Oo cinnamon tortie tabby A- blbl D- Oo fawn tortie aa blbl dd Oo fawn tortie tabby A- blbl dd Oo
You can imagine that it is very difficult to see the red patches in a rich coloured cinnamon tortie or see the cream patches in a dull coloured fawn tortie.  

 

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

You have a red tabby female, but don't know if she is carrying Agouti or not.

Example 1

One way to find out would be to mate her with a black male.
We assume, that both the female and the male don't carry chocolate or cinnamon. Our female can have the following genetic background:
aa BB D- OO or
Aa BB D- OO or
AA BB D- OO
Our black male has the genetic background:
aa BB D- oY

Case 1:
We have a female with
aa BB D- OO

In that case we don't find out, if our female carries Agouti or not, because on the red or red tabby males we can't see if they have Agouti or not.
We could only try to cross them with a black female, if we are lucky we'll get black tabby or tortie tabby kittens. But the chance to keep the wrong little boy - the non-agouti carrier - is quite high.

  male
aBDo aBDY aB-o aB-Y
female aBDO aa BB DD Oo
black tortie females
aa BB DD OY
red or red tabby males
aa BB D- Oo
black tortie females
aa BB D- OY
red or red tabby males
aB-O aa BB D- Oo
black tortie females
aa BB D- OY
red or red tabby males
aa BB -- Oo
black/blue tortie females
aa BB -- OY
red/cream or red/cream tabby males
   
Case 2:
We have a female with
Aa BB D- OO

Here we are more lucky, because on the black/blue tortie tabby females we clearly can make the conclusion that our female must  carry at least one Agouti gene.

  male
aBDo aBDY aB-o aB-Y
female ABDO Aa BB DD Oo
black tortie tabby females
Aa BB DD OY
red or red tabby males
Aa BB D- Oo
black tortie tabby females
Aa BB D- OY
red or red tabby males
AB-O Aa BB D- Oo
black tortie tabby females
Aa BB D- OY
red or red tabby males
Aa BB -- Oo
black/blue tortie tabby females
Aa BB -- OY
red/cream or red/cream tabby males
aB-O aa BB D- Oo
black tortie females
aa BB D- OY
red or red tabby males
aa BB -- Oo
black/blue tortie females
aa BB -- OY
red/cream or red/cream tabby males
aB-O aa BB D- Oo
black tortie females
aa BB D- OY
red or red tabby males
aa BB -- Oo
black/blue tortie females
aa BB -- OY
red/cream or red/cream tabby males
   
Case 3:
We have a female with
AA BB D- OO

Also in that case we only can come to the conclusion that our female must carry at least one Agouti gene, because of the black/blue tortie tabby litter. But with the red boys we still cannot say if they carry Agouti or not.

  male
aBDo aBDY aB-o aB-Y
female ABDO Aa BB DD Oo
black tortie tabby females
Aa BB DD OY
red or red tabby males
Aa BB D- Oo
black tortie tabby females
Aa BB D- OY
red or red tabby males
AB-O Aa BB D- Oo
black tortie tabby females
Aa BB D- OY
red or red tabby males
Aa BB -- Oo
black/blue tortie tabby females
Aa BB -- OY
red/cream or red/cream tabby males
 
[A] [B] [C] [cb & cs] [D] [Dm] [Fd] [I] [L] [Mc] [O] [S] [W] [XY]

 
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