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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 Facts About Dun Horses
Key TraitDetails
Primitive MarkingsDorsal stripe, leg barring, shoulder shadow, ear tips, ventral stripe
GeneDominant Dun gene (D), with d1/d2 alleles affecting markings
PrevalenceUncommon overall; common in Fjord, Mustang, Kiger Mustang, Highland Pony
Ancient LineageDepicted in prehistoric cave art; among the oldest horse colors
A red dun Quarter Horse mare and her foal in a pasture, showcasing dorsal stripe and leg barring on the mare, with the foal's lighter golden dun coat.
“A red dun Quarter Horse foal and her mother with distinctive dun coat color and primitive markings. Source: evelynbelgium.

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:

A dun foal resting, highlighting its clear dorsal stripe and primitive markings.
A dun foal resting, highlighting its clear dorsal stripe and primitive markings. Have a dun foal? Share your story below!
GenotypePhenotype
D/DDun (diluted coat, sharp primitive markings)
D/nd1Dun (diluted coat, sharp primitive markings)
D/nd2Dun (diluted coat, sharp primitive markings)
nd1/nd1Non-dun1 (no dilution, faint markings possible)
nd1/nd2Non-dun1/2 (no dilution, faint markings possible)
nd2/nd2Non-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.

A bay dun horse with a tan coat, dorsal stripe, leg barring, and shoulder shading.
A bay dun horse with a tan coat and black points, showcasing a dorsal stripe and leg barring. Explore more dun colors in the table below.

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)
DDunDun (with 1 copy)Dun (with 1 copy)
d1Dun (with 1 copy)Non-dun1 (may have faint markings)Non-dun1/d2
d2Dun (with 1 copy)Non-dun1/d2Non-dun2 (no markings)
If at least one D is present, the horse will be dun. Only d1/d1, d1/d2, or d2/d2 horses are non-dun.

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.

ColorDescriptionImage
Bay DunTan with black pointsDun displaying a primative pattern.
Red DunApricot with red pointsRed Dun displaying a primative pattern.
GrulloMouse gray with black pointsBlue Dun displaying a primative pattern.
DunalinoPalomino base with dun geneDunolino horse,
DunskinBuckskin base with dun gene Dunskin horse, tan body, black mane, dorsal stripe
Smoky Black DunBlack base with dun geneSmoky black dun horse, dark coat, primitive markings
Silver DunSilver dilution and dun geneSilver dun horse, pale coat, dorsal stripe
Note: Zebra Dun is a descriptive term for duns with pronounced leg barring, not a separate genetic type.

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)
A classic dun horse with various primitive markings, showcasing its leg barring.
Dun quarter horse ready to compete in calf roping event at a rodeo.

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.

MarkingDun HorseBuckskinPalominoRoan
Dorsal Stripe✔️
Leg Barring✔️
Shoulder Shadow✔️
Ear Tips✔️
Ventral Stripe✔️
Non-dun1 horses may show faint markings, but true dun markings are sharp, non-fading, and always present.

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.

FeatureDun HorseBuckskin
GeneDominant Dun gene (D)Cream gene (C^Cr)
Body ColorTan, gold, gray, or redGolden or tan
MarkingsAlways primitive markingsNo primitive markings
Legs/Mane/TailBlack or red, depending on base colorBlack points only
Coat TextureMay have seasonal shadingUniform color year-round
A buckskin horse with a golden coat and black points, compared to a dun horse.
A buckskin horse with a golden coat and black points.
A dun horse with a tan coat and primitive markings, compared to a buckskin horse.
A dun horse with a tan coat and primitive markings, distinct from buckskin.

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.
A dun Norwegian Fjord horse standing in a pasture. The horse has a light tan coat with a dorsal stripe, leg barring, and shoulder stripes.
A dun Norwegian Fjord horse, a breed nearly all dun, with a light tan coat and dorsal stripe.

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

Bay dun quarter horse trotting in an arena.
Bay dun quarter horse trotting in an arena.

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:

YouTube video
A quick look at a dun horse’s dorsal stripe and leg barring in motion. Share your dun horse videos in the comments!

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

Are dun horses rare?

Dun horses are uncommon overall, but common in certain breeds like the Fjord and Mustang.

Can a dun horse have spots?

Yes, if a horse inherits both the dun gene and a spotting gene (like Appaloosa LP).

Are dun horses more expensive?

Dun coloring can be desirable and may increase a horse’s value.

How do I know if my horse is a dun or a buckskin?

Look for sharp, non-fading primitive markings.

Can you breed two duns and get a non-dun foal?

Yes, if both parents carry a non-dun allele.

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

A red dun horse running through snow, featuring a pale reddish coat with a darker red dorsal stripe and leg barring.
A red dun horse running through snow, featuring a pale reddish coat with a darker red dorsal stripe and leg barring. Share your dun photos in the comments!

Dun Horse Myths vs. Facts

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

MythFact
Dun horses are a breedDun is a color, not a breed
All duns have the same markingsMarkings vary by gene and breed
Only Quarter Horses can be dunMany breeds, including Fjord and Mustang, can be dun
All dorsal stripes mean dunSome non-duns (d1) have faint stripes, but true dun stripes are sharp and non-fading
A grullo dun horse with a smoky gray coat, black mane, tail, and lower legs, showing dorsal stripe and leg barring.
A grullo dun horse with a smoky gray coat and black points, displaying a dorsal stripe and leg barring.

🧠 Quiz: How Well Do You Know Dun Horses?

Test your dun horse knowledge! Select the best answer for each question and click Submit.

1. Which marking is a true indicator of a dun horse?


2. What gene is responsible for the dun coat color?


3. Which of these is NOT a dun variation?


4. Dun horses can have which of the following primitive markings?


5. Which base color can the dun gene act on to create a red dun?


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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Examples of dorsal stripes on a classic dun and grullo dun horse, showcasing primitive markings.
Examples of dorsal stripes on a classic dun and grullo dun horse. Source: Wiki Commons. Learn about markings in the Primitive Markings section.

References Section

Miles Henry

About the Author: Miles Henry

Miles Henry is a lifelong horseman with over 25 years of experience owning and training Thoroughbred racehorses. He shares expert insights from his personal experiences growing up with horses, including Quarter Horses and Appaloosas, and currently owns seven Thoroughbreds in training.

Learn more about Miles Henry