The Six Sheltie Colors

Shelties come in six gorgeous colors: Pure Sable, Mahogany Sable, Tri Color, Blue Merle, Bi Black, and Bi Blue. These coats are more than just hues; they're masterpieces of genetics, shaped by the interplay of color distribution patterns like the Irish pattern and Piebald pattern (also known as white factoring). Let's dive into what each Sheltie coat looks like and the fascinating genes behind them.

At a glance: the Sheltie colors.

1. The Pure Sable Sheltie

The Pure Sable Sheltie sports the classic golden coat that instantly evokes images of a pint-sized Lassie. Their fur is a warm, honeyed gold, sometimes deepening into a rich caramel, and always contrasted with crisp white markings on the chest, neck, and legs.

The Pure Sable Sheltie.

Pure Sable puppies start out looking completely different from their adult selves. They're born with soft grayish fur that gradually deepens into that signature warm tan as they grow. Here's our Sable Sheltie puppy, Howard, at 8 weeks old and later at one year old.

A Sable Sheltie in his puppy and adult coat

Our Sable Sheltie, Howard, in his puppy and adult coat.

2. The Mahogany Sable Sheltie

The Mahogany Sable Sheltie carries a more dramatic coat, a deep and layered blend of chestnut and mahogany which is often tipped or heavily overlaid with black.

The Mahogany Sable Sheltie.

Also called Shaded Sable, this coat darkens with age. Take Piper for example: as a one-year-old, he was a warm tan with delicate black highlights, but over the years, those black tips expanded and intensified until his coat was nearly jet black.

A Mahogany Sheltie at different life stages, showing the striking coat development from tan to black

Our Mahogany Sheltie, Piper, at 1 and 15 years, demonstrating the Shaded Sable coat development.

3. The Tri Color Sheltie

Tri Color Shelties wear a striking black coat, dramatically punctuated by patches of warm tan and bright white in the Irish pattern. Their black fur is set off by fiery tan markings above the eyes and on the legs. While black is the most dominant color in many other dog breeds, Shelties break the mold. Their dominant color is Sable, which they share with Rough Collies, Corgis, and Pomeranians. That means the rich black coat of a Tri Color Sheltie is a recessive genetic expression—a hidden treasure brought to the surface only when two parents pass along the right combination.

The Tri Color Sheltie.

4. The Blue Merle Sheltie

Look at this handsome devil. Is this Sheltie steely blue? Is he slate? Is he silver? Only he knows. The rest of us call him a Blue Merle, for his abundance of blue-gray fur, spiced up with a mottled pattern. The effect is known as merling (or dappling in other breeds) and ensures no two Blue Merles look exactly alike.

Genetically, Blue Merles are essentially Tri Colors with a twist. The Merle gene acts like a dilution filter, fading solid black into misty blues and grays. It's as if nature herself played around with the Instagram filter on these pups.

The Blue Merle Sheltie.

5. The Bi Black Sheltie

The Bi Black Sheltie is a bold contrast of jet-black fur and bright white markings. Their coat is velvety dark, untouched by any tan, making their crisp white patches stand out even more dramatically. This high-contrast look is where the “bi” in Bi Black comes from—meaning two colors, black and white.

The Bi Black Sheltie.

6. The Bi Blue Sheltie

The Bi Blue Sheltie is one of the rarest Sheltie colors, a mesmerizing mix of cool-toned gray or blue with the bright white of the Irish pattern. Their coats are often brushed with varying degrees of merling, giving them an ethereal, almost frosted appearance. Genetically speaking, Bi Blues are Bi Blacks with a Merle makeover, their black fur diluted into silvered blue.

The Bi Blue Sheltie.

The Sheltie Color Genes

According to The Colors of the Sheltie: The New DNA Findings, there are at least 11 Sheltie color genes, affecting everything from base color, to patterns, to progressive graying. Here's a quick breakdown of the key genetic terms:

Genes	Units of DNA that control traits (eg, Merle gene).
Alleles	Different "flavors" of a gene (eg, M or m).
Genotype	The allele combo inherited from both parents (eg, MM).
Phenotypes	The physical appearance of a genotype (eg, Double Merle).
Dominant	The most-expressed allele (eg, M).
Recessive	The least-expressed allele (eg, m).

The Merle Gene

Consider the Merle gene, which determines whether dark fur (and eyes) are diluted into lighter shades. Think of it like a watercolor effect:

M (Merle) = Black fur is diluted to blue/gray
m (no Merle) = Black fur is fully retained

Here's a scenario where each offspring has a 75% chance of being Merle. We'll see what the phenotypes look like in a moment. For now, note that the M allele is dominant, meaning it reduces or altogether eliminates the effect of the recessive m allele.

	M = Merle	m = No Merle
M = Merle	MM = Double Merle	Mm = Merle
m = No Merle	mM = Merle	mm = No Merle

The Agouti Gene

Now consider the The Agouti gene, which controls how much tan or black a Sheltie has and whether the fur is banded or solid. This setup is a little more complicated because it comes in three flavors:

a^y (Sable) = Pure or Mahogany Sable
a^t (Tri Color) = Black-dominant Tri Colors
a (Black) = Solid black-and-white Bi Blacks

Here's the possible genotypes of all the Agouti allele pairings. Note that a^y is dominant to a^t which is dominant to a.

	a^y = Sable	a^t = Tri Color	a = Bi Color
a^y = Sable	a^ya^y = Pure Sable	a^ya^t = Mahogany Sable (Tri Factored)	a^ya = Mahogany Sable (Bi Factored)
a^t = Tri Color	a^ta^y = Mahogany Sable (Tri Factored)	a^ta^t = Tri Color	a^ta = Tri Color
a = Bi Color	aa^y = Mahogany Sable (Bi Factored)	aa^t = Tri Color	aa = Bi Color

Phenotypes

Clear as mud, right? Good. Now smash just those two genes together and you get a whole range of coat patterns.


Pure Sable	Mahogany Sable
Agouti: a^ya^y	Agouti: a^ya^t / a^ya
Merle: mm	Merle: mm


Tri Color	Blue Merle
Agouti: a^ta^t / aa^t	Agouti: a^ta^t / aa^t
Merle: mm	Merle: Mm


Bi Black	Bi Blue
Agouti: aa	Agouti: aa
Merle: mm	Merle: Mm

Remember, these are just two color genes in Shelties! With 11 known color genes, each puppy inherits the parental alleles of a whole raft of genes which create diversity in Sheltie colors and patterns.

Double Merles

Sometimes genetic mutation is good—that's evolution. But sometimes it's bad—and that's disease. When two Merle Shelties mate, each puppy has a 25% chance of inheriting the MM genotype, known as the Double Merle. It produces a striking all-white coat but it comes at a severe price. The lack of melanin impacts the development of the eyes and ears in the womb, making many Double Merles blind and deaf.

This is why responsible breeding is so important. And while each individual offspring still has a 75% chance of inheriting a healthy genotype, remember that Shelties typically have litters of four puppies. So, statistically, one puppy in the litter is bound to be born a Double Merle.

Color Headed Whites

Color Headed White Shelties look like normal Shelties who've been dipped in white paint from the neck down. They have solid color heads but nearly all-white bodies. While these rare beauties were disqualified from the breed standard in 1952, they don't suffer the health issues of Double Merles because their white coats come from a different genetic process called White Factoring.

The Color Headed White Sheltie.

White Factored Shelties

White factoring refers to the extent of white markings on the coat. If a dog is White Factored, it means they have an abundance of pure white fur, usually on their collar, chest, and legs, with a strong white stifle running up the back leg.

The White Factored Sheltie.

White Factoring is controlled by the MITF gene, which increases the abundance of white fur.

S (Irish pattern) = Typical white markings on chest and paws
s (White Factored) = Extra white around collar and legs

Crossing two White Factored Shelties (Ss genotype) produce a range of patterns in the offspring, where aach puppy has: a 50% chance of being White Factored, a 25% chance of having the Irish pattern, and a 25% chance of being a Color Headed White.

	s = White Factored	S = Irish
s = White Factored	ss = Color Headed White	sS = White Factored
S = Irish	Ss = White Factored	SS = Irish

White factored Shelties can be valuable to breeders in producing sufficient white markings in puppies. They're prized in dog conformation, as long as the white fur doesn't exceed 50 percent of the body.

Sheltie colors may look like magic, but they're really a masterpiece of genetic combinations. Whether Pure Sable, Mahogany Sable, Tri Color, Blue Merle, Bi Black, or Bi Blue, every Sheltie's coat tells a story written in their DNA.