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Make sure you read "Coat Colour Genetics" first.

 

So how do the two gene pairs, coat colour and expression work?

Remember Black is the dominant coat colour. If the dog has a gene whch gives it the ability to express a dark coat and a dominant Black gene, it will be black.
Look here to see Black dog genetics.

A Chocolate dog must also have the ability to express a dark coat, and must carry two recessive coat colour genes.
Look here to see Chocolate dog genetics.

If the dog carries no dominant Expression gene it will have a yellow or nearly white coat. Yellow is not really a colour, but the absence of colour.
Look here to see Yellow dog genetics.

Passing on traits

So how do two black dogs produce chocolate or yellow puppies? This can happen because the colour of the dogs coat is just the effect of the genes the dog carries. The other genes it carries will be paired with genes from the other parent. So when we say the black dog "carries" a chocolate gene it means he can pass the chocolate coat colour gene on to the next generation. (ie. He has the ability to produce chocolate puppies if paired with another dog carrying chocolate.)

Look here to see more information on passing on coat colour traits.
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Coat Colour Genetics - Labrador Retrievers

All dogs with these genetics will look like this:
This Photo used with permission of VetGen™.
blacklab.jpg - 10599 Bytes BBEE BbEE BBEe BbEe

All dogs with these genetics will look like this:
This Photo used with permission of VetGen™.
blacklab.jpg - 10599 Bytes bbEE bbEe

All dogs with these genetics will look like this:
This Photo used with permission of VetGen™.
blacklab.jpg - 10599 Bytes BBee Bbee

All dogs with these genetics will look like this:
This Photo used with permission of VetGen™.
blacklab.jpg - 10599 Bytes bbee

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Labrador Retrievers come in three colours, Black, Brown and Yellow. How does this happen? Why do Yellow Dogs mated to Yellow only ever produce Yellow puppies? Why do some Black dogs only have Black puppies, no matter what colour the other parent is?

The genetics of coat colour is quite straight forward when you have come to terms with some genetics terms and principles.
(If you know this, go straight to the Chocolate genetics page.)

DOMINANT & RECESSIVE are terms used to describe genes. In Labrador coat colour there are two sets of gene pairs, and the dominant and recessive interplay of these genes will determine the colour of the dogs coat.

Labrador Fact

There are really only two coat colours, Black and Brown. The Yellow dog is not the result of a colour gene, but rather the inability to Express a dark coat colour.

Three principles

Firstly - A Dominant gene will determine the colour of a dogs coat if it is present in the genetic make up, no matter what other gene is present. And so:
Secondly - A Recessive gene can only determine the colour of a dogs coat when no Dominant gene is present.
Thirdly - Genes come in PAIRS, where one part of the gene is inherited from the mother and the other from the father.

Two Labrador Gene Pairs

One gene pair will determine dark coat colour (Black is dominant, Brown is recessive), and another pair are Expression genes: the abiliy to express a dark coat (Dominant) and the inability to express a dark coat (recessive).

All this information is better understood if we use a shorthand way to represent the two sets of gene pairs.

B - black coat colour      b - brown coat colour

E - able to to express a dark coat       e - unable to express a dark coat

By convention, the dominant gene is shown in upper case, the recessive in lower.

A coat colour gene looks like this: BB or Bb or bb

An expression gene looks like this: EE or Ee or ee

The interplay between the dominance issue and the two gene pairs will determine the colour of the dogs coat.

Click here for more detail on coat colour genetics.
All the different ways you can be a labrador - the list.
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If a Black dog mates with a Yellow female, what colour will the puppies be?
The answer depends on the genes each parent carries.
The way the genes can be passed on is written out following a particular pattern.
First the parents genes are written with an x between to indicate a "cross" breeding.
eg. BbEE x BBee
Second: The genes the parents can pass on is written out into two tables.
eg. Taking the example above

Parent 1

 

Parent 2

 

B

b

 

 

B

B

E

BE

bE

 

e

Be

Be

E

BE

bE

 

e

Be

Be


Note that the coat colour genes are put in the top row of the table, and the expression genes are put into the side columns.
The results of this table give us all of the possible genes these two parents can pass on, and with this information, we can create another table to show us all of the types of puppies that could be produced.
All the Genes available from the first Parent are written in the top row, and the all the genes available from the second Parent are written down the column.

Parent 1 - Black (BbEE)

 

 

 

BE

BE

bE

bE

P
a
r
e
n
t

2


Y
e
l
l
o
w



B
B
e
e

Be

Be

Be

Be



So in this mating of a Black dog to a Yellow female, (BbEE x BBee) the only colour puppy produced is Black.
This result comes about because, the Black dog has dominant Expresion genes, (although he carries a gene for chocolate), and the Yellow female carries two dominant colour genes.
In this instance, half of the pups that could be produced would be Black carrying the ability to pass on yellow, and the other half would be Black, carrying both chocolate and yellow.
This 1/2 and 1/2 mix is the genetic probability.

Let's look at Chocolate dog genetics.