Basic Genetics: Diluted coat colours

 

Gene D, d

DENSE gene D

Gene D is responsible that the coat colour will appear "dark", i.e. non-diluted.
It is dominant over its companion d. Therefore gene D must be present only once (Dd) to see its expression that the coat colour appears to be not diluted.

DILUTED gene d

Gene d (=dilution) is recessive, that means it must be present twice (dd) that the coat colour gets diluted.

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

Possible gene combinations

DD homozygous dark coloured Note that non-diluted cats might be homozygous - never pass dilution to their kittens -
or heterozygous - carry dilution and migt pass dilution to their kittens
Dd heterozygous dark coloured
carries dilution
dd homozygous diluted coloured Note that diluted cats are always homozygous for dilution - always pass dilution to their kittens

 

You remember our lesson, where we discussed gene B (Black) ?

Now - only with two genes - we know already the genetic fingerprints of various colours.

Coat colours where gene B and D are involved
non diluted colour gene combination diluted coat colour gene combination
black BB DD BB Dd blue BB dd
Bb DD Bb Dd Bb dd
Bbl DD Bbl Dd Bbl dd
chocolate bb DD bb Dd lilac bb dd
bbl DD bbl Dd bbl dd
cinnamon blbl DD blbl Dd fawn blbl dd

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

When you look on our table above you see, black or blue cats are full of surprises, they might carry various genetic informations which you don't see from outside. You can find out the genetic background of your black cat only by test mating.
With cinnamon and fawn cats it is quite easier, they can inherit only one colour either cinnamon or fawn. From cinnamon cats you can get only cinnamons or fawns (if they carry dilution).

You have a black female and want to find out what she carries.

Example 1: We breed for orientals
Note: On orientals you might have all colours: black/blue, chocolate/lilac and cinnamon/fawn The best way is to use a fawn male. It carries double dilution (dd) and carries the cinnamon gene double (blbl).
Our female can have various gene combinations - as you have seen on the table above:
BB DD, BB Dd, Bb DD, Bb Dd, Bbl DD, Bbl Dd
Let's start to build up our tables !

female's gene combination:
BB DD		 male
bld
female BD Bbl Dd
all kittens are black

That is the worst case, all kittens are black.
We only know all carry cinnamon and dilution, but about our female we still don't know more.
female's gene combination:
BB Dd		 male
bld
female BD Bbl Dd
black,
carry cinnamon and dilution
Bd Bbl dd
blue,
homozygous for dilution and carry cinnamon

That's already better, on the blue kittens we see that our female carries dilution, even she's black.
female's gene combination:
Bb DD		 male
bld
female BD Bbl Dd
black,
carry cinnamon and dilution
bD bbl Dd
chocolate,
heterozygous, carry cinnamon and dilution

On the chocolate kittens we see that our female carries chocolate, even she's black.
female's gene combination:
Bb Dd		 male
bld
female BD Bbl Dd
black,
carry cinnamon and dilution
Bd Bbl dd
blue,
homozygous for dilution and carry cinnamon
bD bbl Dd
chocolate,
carry cinnamon and dilution
bd bbl dd
lilac,
homozygous for dilution and carry cinnamon

If we are lucky and get a lilac kitten we know that our female carries chocolate and dilution. But even if we get only blue and chocolate kittens we know the same.
female's gene combination:
Bbl DD		 male
bld
female BD Bbl Dd
black,
carry cinnamon and dilution
blD blbl Dd
cinnamon,
homozygous for cinnamon and carry dilution

If we get a cinnamon kitten we know that our female carries cinnamon. But we still don't know if our female carries dilution. We do know that all our kittens must carry the dilution at least from their father.
female's gene combination:
Bbl dd		 male
bld
female BD Bbl Dd
black,
carry cinnamon and dilution
Bd Bbl dd
blue,
homozygous for dilution and carry cinnamon
blD blbl Dd
cinnamon,
carry dilution
bld blbl dd
fawn,
homozygous for cinnamon and dilution

If we get a fawn kitten we know that our female carries cinnamon and dilution. But even if we get only blue and cinnamon kittens we know the same.


Example 2: We breed for persians
Note: On persians you might have the colours: black/blue, chocolate/lilac. Normally the colours cinnamon/fawn don't exist on persians.
The best way to find out what our black female might carry is to use a lilac male. It carries double dilution (dd) and carries the chocolate gene double (bb).
Our female can have various gene combinations - as you have seen on the table above:
BB DD, BB Dd, Bb DD, Bb Dd
Let's start to build up our tables !

female's gene combination:
BB DD		 male
bd
female BD Bb Dd
all kittens are black

That is the worst case, all kittens are black.
We only know all carry now chocolate and dilution, but about our female we still don't know more.
female's gene combination:
BB Dd		 male
bd
female BD Bb Dd
black,
carry chocolate and dilution
Bd Bb dd
blue,
homozygous for dilution and carry chocolate

That's already better, on the blue kittens we see that our female carries dilution, even she's black. Note that all kittens will carry chocolate, too - it comes from their father.
female's gene combination:
Bb DD		 male
bd
female BD Bb Dd
black,
carry chocolate and dilution
bD bb Dd
chocolate,
homozygous for chocolate and carry dilution

On the chocolate kittens we see that our female carries chocolate, even she's black. Note that all kittens carry dilution - it comes from their father.
female's gene combination:
Bb Dd		 male
bd
female BD Bb Dd
black,
carry chocolate and dilution
Bd Bb dd
blue,
homozygous for dilution and carry chocolate
bD bb Dd
chocolate,
carry dilution
bd bb dd
lilac,
homozygous for dilution and chocolate

If we are lucky and get a lilac kitten we know that our female carries chocolate and dilution. But even if we get only blue and chocolate kittens we know the same.

 

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Last modified on  99-02-24

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