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# Chestnut non-dun1
- URL: https://equinecolors.com/chestnut-nd1/
- Published: 2025-11-26T11:38:20.000Z
- Updated: 2026-07-30T10:51:16.000Z
- Description: Chestnut non-dun1 (or nd1) is a horse color caused by nd1 on a chestnut base. Primitive markings are present.
- Author: Hannelore Roodhooft
- Tags: Colors, Dilutions, #Import 2026-08-12 09:42

## Appearance

| Foals | ![Chestnut non-dun1 foal](https://equinecolors.com/content/images/2025/11/chestnutnd1foal.png) | Regular [chestnut](https://equinecolors.com/chestnut/) color with darker red[**primitive markings**](https://equinecolors.com/dictionary/#:~:text=a%20bay%20horse.-,Primitive%20markings,-Primitive%20markings%20may). Leg primitivesmay be harder to see. |
| ----- | ---------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |

| Non-dun1 on a **chestnut base** causesdarker red **primitive markings**. The dorsalstripe is usually the most notable. | ![Chestnut non-dun1](https://equinecolors.com/content/images/2025/11/chestnutnd1-1.png) | Adults |
| ---------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------- | ------ |

### Chestnut variations

| Flaxennd1 | ![Flaxen chestnut nd1](https://equinecolors.com/content/images/2026/01/flaxennd1.png) |
| --------- | ------------------------------------------------------------------------------------- |

| Sootynd1 | ![Sooty chestnut nd1](https://equinecolors.com/content/images/2026/01/sootynd1.png) |
| -------- | ----------------------------------------------------------------------------------- |

### Mimics

Chestnut horses with nd1 may look similar to chestnut dun.

💡

The ****dun dorsal stripe** goes through the ****tail**, while nd1 dorsal stripes don’t.  
****Dun** is more likely to cause ****striping** at the ****back** of the ****ears** than nd1.  
Foals with ****dun** tend to have a ****darker lower face** mask, while nd1 foals have a darker forehead.

## Genetics

Chestnut non-dun1 is the result of a **chestnut base** with **one or two copies of nd1**. Non-dun1 (nd1) is an allele of the **TBX3** gene.

![CTA Image](https://equinecolors.com/content/images/2025/12/Equinecolors_Icon_DNA1-25.png) 

****Chestnut nd1:**  
Chestnut (e/e) + nd1/nd1  
Chestnut (e/e) + nd1/nd2

Dun (D), located on the same gene, is dominant over nd1, so horses could carry nd1 without it being noticeable but still pass it on.  

**Read more:**  
[Chestnut](https://equinecolors.com/base-colors-chestnut/) | [Black nd1](https://equinecolors.com/black-nd1/) | [Bay nd1](https://equinecolors.com/bay-non-dun1/)

[Back to Non-dun1](https://equinecolors.com/nd1/)

## Articles

1. Imsland, F., McGowan, K., Rubin, C. J., Henegar, C., Sundstrom, E., Berglund, J., Schwochow, D., Gustafson, U., Imsland, P., Lindblad-Toh, K., Lindgren, G., Mikko, S., Millon, L., Wade, C., Schubert, M., Orlando, L., Penedo, M. C., Barsh, G. S., & Andersson, L.; **Regulatory mutations in TBX3 disrupt asymmetric hair pigmentation that underlies Dun camouflage color in horses**; Nature Genetics (2015)*;* Doi: [10.1038/ng.3475](https://doi.org/10.1038/ng.3475?ref=equinecolors.com)[](https://www.researchgate.net/journal/Genes-2073-4425?ref=equinecolors.com)

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