Dun Horse: Color Genetics, Markings & Breeds (Complete Guide)

Last updated: June 10, 2025

By: Miles HenryFact Checked

The dun horse captivates with its unique diluted coat, primitive markings, and ancient lineage. This complete guide explores dun horse genetics, colors, markings, breeds, care, and more—making it the ultimate resource for enthusiasts and owners alike.

Quick Navigation: Select a Section Dun Horse Genetics Dun Color Inheritance Dun Horse Colors & Patterns Primitive Markings Dun vs. Buckskin Dun Horse Breeds Famous Dun Horses Caring for a Dun Horse FAQs Myths vs. Facts Conclusion References

Quick Facts About Dun Horses

Key Trait	Details
Primitive Markings	Dorsal stripe, leg barring, shoulder shadow, ear tips, ventral stripe
Gene	Dominant Dun gene (D), with d1/d2 alleles affecting markings
Prevalence	Uncommon overall; common in Fjord, Mustang, Kiger Mustang, Highland Pony
Ancient Lineage	Depicted in prehistoric cave art; among the oldest horse colors

Dun Horse Genetics

Dun horses are renowned for their distinctive coat colors and primitive markings, such as dorsal stripes and leg barring, which reflect their ancient ancestry. These features are not only visually striking but also provide insight into equine genetics and evolution.

The dun coloration is controlled by the dominant dun gene (D), which dilutes the horse’s base coat color—bay, black, or chestnut—while preserving darker “primitive markings.” This gene can act on any base color: bay (producing classic dun), black (producing grullo), or chestnut (producing red dun). Horses with at least one copy of the D allele (D/D, D/nd1, or D/nd2) will display dun characteristics.

There are two non-dun variants, sometimes referred to as d1 and d2 in older literature:

• Non-dun1 (nd1): No dilution, but faint primitive markings may appear (though they are never as sharp or consistent as in true dun horses).
• Non-dun2 (nd2): No dilution and no primitive markings.

Genotype and Phenotype Summary:
This table summarizes how different combinations of the dun gene and its variants affect a horse’s appearance:

Genotype	Phenotype
D/D	Dun (diluted coat, sharp primitive markings)
D/nd1	Dun (diluted coat, sharp primitive markings)
D/nd2	Dun (diluted coat, sharp primitive markings)
nd1/nd1	Non-dun1 (no dilution, faint markings possible)
nd1/nd2	Non-dun1/2 (no dilution, faint markings possible)
nd2/nd2	Non-dun2 (no dilution, no primitive markings)

The dun gene’s effect is caused by regulatory mutations in the TBX3 gene. Dun is considered the ancestral (wild-type) color of wild horses, while non-dun1 and non-dun2 alleles are more common in modern domesticated breeds.

According to the UC Davis Veterinary Genetics Laboratory, dun gene tests are accurate up to 95% (2024), and dun coloration appears in 10–15% of wild horse populations. Environmental factors can influence the appearance of dun horses—some may look darker in winter and lighter in summer. For a deeper understanding of horse color genetics, see The Science of Horse Coat Colors: Deep Dive.

As a breeder, I’ve seen dun foals develop their markings over time—often with the dorsal stripe showing first. You can confirm your horse’s genetic status through a UC Davis DNA test for the dun gene. Have you tested your horse’s genetics? Share your results in the comments below!

Dun Color Inheritance

Understanding how dun color is inherited can help breeders predict foal color outcomes. The Punnett square below shows how different combinations of the dun gene (D) and its non-dun variants (d1 and d2) from each parent affect a foal’s color.

If a foal inherits at least one D allele, it will be dun and display classic primitive markings. Only foals with two non-dun alleles (d1 and/or d2) will lack the dun dilution—though those with d1 may still show faint markings. This chart helps breeders predict the likelihood of dun or non-dun offspring based on the parents’ genetics.

Dun Color Inheritance Chart (Punnett Square):

	D (Dun)	d1 (Non-dun1)	d2 (Non-dun2)
D	Dun	Dun (with 1 copy)	Dun (with 1 copy)
d1	Dun (with 1 copy)	Non-dun1 (may have faint markings)	Non-dun1/d2
d2	Dun (with 1 copy)	Non-dun1/d2	Non-dun2 (no markings)

Dun Horse Colors & Patterns

Dun horses come in a variety of shades, each influenced by their base coat color and the action of the dun gene. The table below highlights the most common dun color variations, their descriptions, and visual examples.

Color	Description	Image
Bay Dun	Tan with black points
Red Dun	Apricot with red points
Grullo	Mouse gray with black points
Dunalino	Palomino base with dun gene
Dunskin	Buckskin base with dun gene
Smoky Black Dun	Black base with dun gene
Silver Dun	Silver dilution and dun gene

How to Spot Dun Markings vs. Lookalikes

Dun horses are defined by their sharp, well-defined primitive markings, which set them apart from other coat colors. These distinctive features include:

• Dorsal stripe (dark line down the back)
• Leg barring (zebra-like stripes)
• Shoulder shadow (dark patch across shoulder)
• Ear tips (subtle but reliable indicator)
• Ventral stripe (dark line along the belly)

Comparison Table:

The table below compares the key primitive markings found on dun horses with those of similar coat colors, helping you identify true dun traits at a glance.

Marking	Dun Horse	Buckskin	Palomino	Roan
Dorsal Stripe	✔️	❌	❌	❌
Leg Barring	✔️	❌	❌	❌
Shoulder Shadow	✔️	❌	❌	❌
Ear Tips	✔️	❌	❌	❌
Ventral Stripe	✔️	❌	❌	❌

Dun vs. Buckskin: Key Differences

Dun and buckskin horses are often confused because of their similar golden coats and dark points, but they are genetically and visually distinct. The table below highlights the key differences between these two popular colors.

Feature	Dun Horse	Buckskin
Gene	Dominant Dun gene (D)	Cream gene (C^Cr)
Body Color	Tan, gold, gray, or red	Golden or tan
Markings	Always primitive markings	No primitive markings
Legs/Mane/Tail	Black or red, depending on base color	Black points only
Coat Texture	May have seasonal shading	Uniform color year-round

Dun Horse Breeds

Dun coloring is found in a variety of breeds, but its prevalence ranges from almost universal to quite rare. Here’s how common dun horses are in some popular breeds:

• American Quarter Horse: About 5–10% of registered Quarter Horses are dun; many registry champions are dun. Dun is a recognized and accepted color in the AQHA. For a complete list of all colors accepted by the registry, see the AQHA’s official color and markings guide
• Mustang: Dun is highly prevalent, especially in Kiger Mustangs (estimated 20–30% in some wild herds).
• Norwegian Fjord: Nearly all (over 90%) are dun; dun is a defining feature of the breed. Learn more about the Norwegian Ford Horse Breed.
• Highland Pony: Dun is recognized and relatively common, accounting for approximately 30–40% of the population.
• Icelandic Horse: Dun variations occur but are less common (around 10–15%).
• Appaloosa: Dun is a rare color, found in fewer than 5% of Appaloosas. See the Appaloosa Horse Breed Profile for a detailed look at this unique American breed.

To explore another breed known for its striking spotted patterns, check out the American Paint Horse Comprehensive Guide.

For official breed standards and color registration, visit the American Buckskin Registry Association and the International Buckskin Horse Association, which recognize and register dun and buckskin horses.

Famous Dun Horses

Throughout history and popular culture, several dun horses have stood out for their achievements, influence, or iconic status. Here are a few of the most famous dun horses:

• Spirit (Spirit: Stallion of the Cimarron): Based on a real dun Kiger Mustang who inspired the animated film’s main character.
• Hollywood Dun It: Legendary Quarter Horse sire.
• Dun Deal: AQHA World Champion. Explore more about the versatile Quarter Horse Breed.
• Doc Bar: Inducted into the AQHA Hall of Fame in 1993, he sired many successful offspring.
• Doc O’Lena: A champion cutting horse and son of Doc Bar, he was inducted into the AQHA Hall of Fame in 1977.
• Zippos Mr. Good Bar: A red dun horse inducted into the AQHA Hall of Fame in 2019, known for his athleticism and successful offspring.

Caring for a Dun Horse

While dun horses do not require special care compared to other colors, a few simple routines can help keep their distinctive markings and coats in top condition. Regular grooming is essential—not only to highlight their unique features, but also to monitor their overall health. For a step-by-step guide to daily grooming and early health detection, see Daily Horse Grooming: Detect Health Issues Early.

• Coat Care: Gentle shampoos, regular grooming to highlight markings.
• Hoof Care: Regular trimming helps keep leg barring visible.
• Skin Sensitivity: Duns may have sensitive skin—provide shelter in summer.
• Diet: No special requirements due to color.
• Seasonal Changes: Expect color to lighten in summer, darken in winter.

For more tips, read our Horse Coat Colors & Patterns guide.

Watch this short video to see the distinctive primitive markings of a dun horse in action:

FAQs About Dun Horses

Here are answers to some of the most common questions about dun horses to help you better understand this unique coat color

For more on horse genetics, see our guide on equine genetics.

Dun Horse Myths vs. Facts

Many misconceptions surround dun horses and their markings. Here’s the truth behind the most common myths:

Myth	Fact
Dun horses are a breed	Dun is a color, not a breed
All duns have the same markings	Markings vary by gene and breed
Only Quarter Horses can be dun	Many breeds, including Fjord and Mustang, can be dun
All dorsal stripes mean dun	Some non-duns (d1) have faint stripes, but true dun stripes are sharp and non-fading

🧠 Quiz: How Well Do You Know Dun Horses?

Conclusion

Dun horses, with their ancient markings and vibrant colors, offer a unique appeal to horse lovers and breeders alike. Thinking of buying a dun horse or curious about your own horse’s coat? Share your experience or ask questions in the comments—we’d love to hear your story!

🐴 Have a dun horse or want to identify one? Drop your photos or questions in the comments!

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References Section

• UC Davis Veterinary Genetics Laboratory: Dun Gene (2024) — Data as of May 2025.
• American Quarter Horse Association: Dun Characteristics — Data as of May 2025.
• Norwegian Fjord Horse Registry — Data as of May 2025.
• Horse Coat Colors & Patterns
• Buckskin Horse Profile
• Quarter Horse Breed Guide
• How to Read a DNA Test
• Appaloosa Horse Breed Profile
• AQHA: Quarter Horse Markings and Color Genetics (Official Color Chart)
• American Paint Horse Comprehensive Guide
• The Science of Horse Coat Colors: Deep Dive
• Horse Colors & Coat Patterns Guide: Color Genetics
• American Buckskin Registry Association
• International Buckskin Horse Association