Predicting the colour of Labrador retriever puppies

The Labrador retriever is a large, friendly dog breed that reliably makes the top five list of the most popular breeds of dog within the UK. The coat of the Labrador is always one colour, and the three accepted shades for the coat are black, yellow and chocolate respectively, and these are the three colours that are recognised by The Kennel Club as acceptable shades in pedigree dogs. However, in reality, the Labrador’s three colours can be found in a reasonably wide variety of shades, ranging right down to cream in yellow labs, to fox red in chocolates.

Knowing what colour the puppies in any given Labrador litter will be can be hard to predict, and the colour of the two parent dogs does not always ensure the colouring of the pups!

In order to gain a better understanding of how the coat colour for any given Lab is ascertained, a basic understanding of the genetics of the coat, and how colour is passed from generation to generation is needed. We will look at these factors in more detail within this article.

Chocolate and black Labradors

What causes any given Lab to be either chocolate or black depends on the genes that they inherit, and these are called the “B” or “Bee” genes. All Labradors inherit two B genes, with one coming from each of their parents. B genes come in two types:

• Big B, for a dominant gene, which causes the black coat colour.
• Little b, for the recessive gene, which leads to the chocolate coat colour.

If the dog in question inherits a big B gene, this effectively “turns off” the brown gene, and so any dog that has one parent with a big B gene will be black. Because two genes are passed on, one from each parent, there are three possible B gene combinations:

Two big B’s.

Two little b’s.

One of each.

This means that only if the dog inherits two little b’s will the dog be chocolate coloured; any big B gene cancels out the little b, leading to a black coat. However, dogs with one of each B genes will be able to pass on the brown gene to their pups.

Yellow Labradors

The genes that are responsible for the yellow Labrador coat are due to an entirely different pair of genes from the B genes. These are referred to as the E genes.

There are two types of E genes:

• Big E, which is a dominant gene, but does not affect the B gene.
• Little e, which is a recessive gene, but can potentially override the B gene, which causes the resulting pup to be yellow. This is known as a masking gene.

Each pup inherits two of the E genes, one from each parent. If the dominant E gene is present, this turns off the masking gene, meaning that the dog will only be yellow if there is no E gene in play. There are again, three potential ways in which the dog can inherit the pair of E genes:

• Two dominant or big E genes.
• Two recessive, or little e masking genes.
• One of each type of E genes.

Dogs that inherit two little e genes will be yellow, while for dogs with two big E genes or one of each type of E gene, the E gene essentially becomes dormant, and the colouration of the dog will fall back to the equation listed further up for the B genes.

The potential colour combinations by gene

There are a total of nine different possible gene combinations between the B and E genes, which we will list below. In this list, big B genes are expressed with a capital letter, while little b is expressed with a small letter. The same goes for the E genes, and so each dog will have a total of four letters in varying combinations.

• EEBB= Black coat
• EEBb= Black coat
• EEbb= Brown coat
• EeBB= Black coat
• EeBb= Black coat
• Eebb= Brown coat
• eeBB= Yellow coat
• eeBb= Yellow coat
• eebb= Yellow coat

Predicting what colour Labrador puppies will turn out to be

Without knowing which genes each parent dog possesses and so, passes onto their pups, predicting their colour prior to birth is rather hard. This is because the actual colour of the parent dogs is not what influences the colour of the litter, as despite the colour that they display, they may also possess the genes for other variants.

Just about the only certainties that you can rely on when it comes to breeding colours is that two yellow Labradors mated will always produce yellow Labradors, and that two brown Labradors mated will not produce black Labradors. In every other instance the colour of the pups will depend on the gene combinations of the parent dogs, which can only be ascertained by genotype testing of the parent dogs prior to breeding, to identify the potential options that they might produce.