Coat Colours | Vycaran Collies

Coat Colours in the Rough Collie

Written by Atlanta Jackson, Vycaran Collies. Originally published in 2020

The Rough and Smooth Collies come in a few different coat colours. These colours are the same all around the world, however the Kennel Club breed standard for the Collie varies between countries. Because of this, some colours are not bred as frequently in the UK or Europe as they are in America, even though they occur naturally. These colours might be available infrequently, but it is recommended you don't get your heart set on a coat colour that may only show up every few years! The chart below shows the colours each country recognises in their breed standard, and therefore the colours usually available and which can be shown in conformation shows.

Breed Standards (Colours by Country)

The chart above shows the 'recognised' colours in each country, and the colours which can be shown. However, all of the colours occur naturally occur within the Collie gene pool.

FCI standard countries include Europe and Australia.

UK and FCI Standard

US Standard

Colours

Now we will take a look at each colour.

Sable

Sable can range in colour from a light straw colour to a deep mahogany. Light straw is undesirable, a golden - mahogany tone is favoured. Sable can come in two forms - 'Pure' Sable, and Tri-Factored Sable. Pure Sables are usually lighter in colour, and have two copies of the Sable gene.

Tri-Factored Sable

This is the other form of sable, sometimes called 'shaded sable' or 'mahogany sable'. Tri-Factored sables are often darker, may have a dark widow's peak marking on their foreheads, and often have a 'cape' of black banded hairs. Their colour can change with their coats, and they sometimes become darker as they age. Tri-Factored sables are called this as they carry a Tricolour gene, which is recessive to the Sable gene, but interacts with it in such a way that it is able to show through the Sable (hence the dark cape).

Tricolour

Tricolours are black dogs, with tan points and the usual white Collie markings - three colours, hence the name. Their tan points can vary in colour intensity, some being quite pale, some being richer.

Blue Merle

Blue Merles are genetically Tricolour Collies, that have inherited the Merle gene. The Merle gene can turn parts of the coat lighter, making them grey, and sometimes can delete pigment entirely to make patches of white. The Merle gene itself has a tail called a 'Poly-A tail', and the different lengths of tail produce different effects. Because of this, Blue Merles can come in a wide variety of colours, from almost completely white, to pale, silvery blue, to darker grey and even sometimes appear almost completely black (Tricolour). You can read more about this here. Their black patches can also vary in size, with larger patches, smaller 'mottles', or larger sections that may even cover whole body parts! The most desirable colour of Blue Merle, and the one requested in the Breed Standard, is for a light silver, splashed and marbled with black patches of smaller or larger size.

Sable Merle

The Merle gene can also affect Sables, although the effects are slightly different. Merle can only affect black pigment, called 'Eumelanin', whereas Sable is caused by red/brown pigment, called 'Pheomelanin'. Because of this, Merle can't affect the majority of the Sable coat, and very often the Merle is not visible at all on Sable Merles. Tri-Factored Sables Merles, who have a tri gene causing black banded hairs, can sometimes be recognised as Sable Merle. This is because the black parts of the hair can be affected by the Merle gene. So, a Tri-Factored Sable merle may have patches in their black banded areas, with these patches appearing lighter sable. To differentiate them from Sable non-merles, in our Collie drawings the Sable Merles have a small white patch, even though this is not realistic!

Colour Headed White

The gene that causes White Collies is called 'Piebald'. A White Collie will be genetically Sable, Sable Merle, Tricolour, or Blue Merle, with the Piebald over the top. Because of this, they often have coloured markings on their head and face, and sometimes patches on their bodies. We call them 'Colour Headed White' (often abbreviated to CHW) for this reason. This means you can get Colour Headed White Collies with any of the Collie colours on their heads, or in body patches.

Homozygous Merles

Homozygous Merles are often referred to as 'Double Merles', and also incorrectly referred to as 'Double Dilutes' or 'Lethal Whites'. They should not be confused with Colour Headed White Collies, which do not suffer from the same effects.

Colour Inheritance

In the Rough and Smooth Collie breeds we have two 'building blocks' of coat colour - sable and tricolour. All other coat colours are based on these two colours.

Genetically, these colours are both from genes on the 'A locus'. This means that both sable and tricolour are built by genes in the same area, within our collie's genetic code. The options that Rough Collies have on the A locus are sable (Ay) and tricolour (at).

Sable vs Tricolour

In this A locus, sable is dominant over all 4 of the alleles in this series. This means if a dog inherits one copy of Ay / sable, the dog will be sable. This is the reason sable uses a capital A in Ay. Tricolour is recessive, so uses a small a in at.

However, Ay / sable is incompletely dominant over tricolour / at. This is what causes the tri-factored sable coat colour. The tricolour gene is suppressed by the sable gene but some of it is 'showing through' the coat. That is what causes the black hairs on tri-factored sables.

That means there are 3 combinations a collie can inherit on the A locus:

Ay / Ay (pure or homozygous sable)
Ay / at (tri-factored sable)
at / at (tricolour)

Merle Pattern

A merle collie is just one of those combinations with a merle modifier over the top. Therefore a merle collie is just tricolour or sable, with the merle pattern overlaid.

Merle is a pattern that only affects the black parts of the coat (otherwise known as eumelanin). That's the reason tricolours become blue merle when the merle pattern is overlaid - the black parts of the coat lighten leaving patches of black. However in sable dogs, there is much less eumelanin in the coat. The warm brown colour of a sable is produced by the opposite pigment to black, called pheomelanin. Merle doesn't affect it, so for the most part, sable merles just look like sables.

Merle is dominant, therefore if a collie has a copy of the merle gene it will be merle, and merle can't be 'carried' (as it is dominant and will always be expressed). There are occasions in which a dog that's genetically merle won't 'look' merle. Find out more in the separate article I've uploaded on the merle gene.

Sable merle collies will be one of the following combinations:

Ay / Ay M / m (pure or homozygous sable, merle)
Ay / at M / m (tri-factored sable, merle)

Blue merle collies will be at / at M / m (tricolour, merle).

Double merle dogs can have any combination of Ay and at and will be M / M.

White Collies, White Factor and White Markings

Irish spotting is the gene that causes the classic collie markings: including the white collar, white feet, and tail tip, among others. All collies have two copies of the gene (this means they all express irish spotting to a greater or lesser extent). Irish spotting is denoted as si in genetics, however it is thought to be located on another locus to the S series. We just don't know which one yet!

White collies (colour headed whites) are caused by a gene for piebald. If a collie inherits two piebald genes (sp), it will become piebald - what we call a colour headed white.

White factoring is the term for when a collie has additional white markings in addition to the irish spotting markings. They aren't colour headed whites, as they are almost completely their usual colour, but they have more white than others. This is caused when the collie has inherited one copy of piebald only (sp).

So knowing all collies have 2 alleles for white spotting (si), here are the combinations we have on the S locus:

si / si S / S (irish spotting, no white factoring)
si / si S / sp (irish spotting, white factored)
si / si sp / sp (irish spotting, white collie / extended white factoring)

Breeding two white factored dogs together can produce collies of all the S locus varieties.

In the diagram below, the white factored collies are represented as the tri coloured dogs that have white above their hock (further up their rear legs). However it's important to note that only a DNA test can confirm the presence of a piebald gene, as some white factored collies display no additional markings, and some non-carriers have additional white.

In Conclusion

There are three building blocks that make up the colour of our collies.

Sable vs Tricolour (AKA the A locus)
Merle
White Markings (AKA the S locus)

To find out the genetics of your collie, work out the following:

Is my collie sable or tricolour based? Look for tan markings on the face, which they'll have if they're tricolour based. If all of their body has the tan colour, they're sable based.
Does my collie have the merle gene? For blue merles this is obvious, however you need to factor in the consideration that merle can sometimes not be visible in the adult coat. Always get a merle genetic test for collies before breeding.
What white markings does my collie have? The usual 'collie markings' aka irish spotting? Does it have a few more of those markings, or extended versions, such as white up the leg? If so, it may carry piebald, but this isn't certain.

Before breeding, you'll therefore need the following coat colour tests:

A locus
S locus
Merle

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