Understanding the Wild Type Gene in Highland Cattle

History, Appearance, and Breeding Decisions for Coat Color 

Highland cattle are famous for their remarkable range of coat colors—reds, yellows, blacks, duns, silvers, and brindles—often within the same herd. While traditional Highland terminology has described these colors for centuries, modern genetics now explains why they occur. One of the most important (and often misunderstood) concepts in Highland coat color genetics is the Wild Type gene, commonly referred to as E⁺. 

This article explains what the Wild Type gene is, where it comes from, how it appears in Highland cattle, and how it should influence breeding decisions—especially when coat color matters. 

What Does “Wild Type” Mean in Genetics? 

In genetics, wild type refers to the original or ancestral version of a gene—the form that existed before mutations created alternative versions. It does not mean “unimproved” or “undesirable.” In fact, wild type alleles often allow more variability than mutated ones. 

In cattle coat color genetics, “wild type” almost always refers to the E⁺ allele at the Extension locus, which is controlled by the MC1R gene. 

The Extension (E) locus has three primary functional alleles in cattle: 

• Eᴰ – dominant black 

• E⁺ – wild type 

• e – recessive red 

Among these, E⁺ is the ancestral allele and remains especially important in heritage breeds like Highlands. 

A Brief History of the Wild Type (E⁺) Gene in Cattle 

Before DNA testing existed, early geneticists studied coat color inheritance through observation. Highlands were known to produce: 

• Red calves from dark parents 

• Brindle calves from non-brindle parents 

• Wide variation in shade even within the same color category 

Modern molecular studies eventually identified the MC1R gene as the control point for whether hair follicles produce black/brown pigment (eumelanin) or red/yellow pigment (pheomelanin). 

The E⁺ allele represents the original regulatory form of this gene—one that can respond to signals from other color genes instead of forcing a single outcome. This flexibility explains much of the visual diversity seen in Highland cattle today. 

How the Wild Type (E⁺) Gene Appears in Highland Cattle 

1. Variable Base Color 

Unlike dominant black (Eᴰ) or recessive red (e/e), E⁺ does not lock the animal into a single pigment outcome. Highlands carrying E⁺ may appear: 

• Red, yellow, or reddish-brown 

• Dark brown or nearly black 

• Shaded with darker points (muzzle, ears, legs) 

 This variability is normal and expected with E⁺. 

2. Brindle Expression (Critical Role) 

One of the most important roles of E⁺ in Highlands is that it allows brindle striping to appear. 

Brindle generally requires: 

• At least one E⁺ allele at the Extension locus, and 

• A brindle allele at the Agouti locus (often labeled Aᵇʳ) 

Without E⁺, brindle patterning is usually suppressed—even if the animal carries brindle genetically. This is why some Highlands can carry brindle but never show it phenotypically. 

3. Masking Effects 

An animal may genetically carry E⁺ but not visibly express its effects due to masking: 

• Eᴰ (dominant black) masks brindle and most variation 

• e/e (recessive red) fixes red pigment and limits pattern expression 

This explains why DNA testing often reveals “hidden” color potential. 

Wild Type and Highland Color Variations 

Highland colors such as dun and silver are not controlled by the Extension locus alone. These involve dilution modifiers, most commonly associated with the PMEL gene, which lightens black pigment. 

As a result: 

• A genetically black-based animal can appear dun or silver 

• An E⁺ animal can express a wide range of diluted or undiluted tones 

This layered genetic interaction is why Highlands often defy simple color prediction. 

How the Wild Type Gene Influences Breeding Decisions 

1. Coat Color Predictability 

Breeders aiming for specific colors—especially brindle—must account for E⁺. Visual phenotype alone is unreliable. Two non-brindle parents can produce brindle calves if: 

• Both carry E⁺ 

• A brindle allele is present 

2. Managing Expectations 

E⁺ introduces variability, not certainty. Even with correct alleles present: 

• Brindle intensity can vary 

• Shade may change with age or season 

• Modifier genes may influence expression 

3. Importance of Genetic Testing 

Because E⁺ can be masked, breeding programs often test for: 

• MC1R (Extension) 

• PMEL (dilution) 

• Pattern loci where available 

Organizations like University of California, Davis Veterinary Genetics Laboratory provide industry-standard testing that removes guesswork from breeding decisions. 

Why the Wild Type Gene Matters in Highlands 

Highland cattle are a heritage breed defined by genetic diversity and adaptability. The Wild Type (E⁺) gene preserves that diversity by allowing interaction between color genes rather than forcing uniformity. 

Understanding E⁺ helps breeders: 

• Avoid oversimplified color claims 

• Explain unexpected outcomes honestly 

• Make informed, breeding decisions 

Rather than being a complication, E⁺ is part of what makes Highlands genetically rich and visually distinctive. 

Clear Answer 

The Wild Type gene in Highland cattle refers to the E⁺ allele at the MC1R (Extension) locus. It is the ancestral form of the gene and allows flexible pigment expression, enables brindle patterning, and contributes to the wide color variation seen in the breed. Its presence—and interaction with other genes—plays a major role in coat color outcomes and breeding decisions. 

Key Caveats 

• Brindle and shade intensity are influenced by additional modifier genes not fully mapped 

• Phenotype alone cannot reliably identify E⁺ carriers 

• Breed terminology may not always align perfectly with molecular genetics 

References

American Highland Cattle Association. (n.d.). Highland cattle color standards and breed history. https://highlandcattleusa.org 

Cieslak, M., Reissmann, M., Hofreiter, M., & Ludwig, A. (2011). Variation in the MC1R gene and its association with coat color in cattle. Journal of Animal Breeding and Genetics, 128(3), 193–200. https://doi.org/10.1111/j.1439-0388.2010.00905.x 

Klungland, H., Våge, D. I., Gomez-Raya, L., Adalsteinsson, S., & Lien, S. (1995). The role of melanocyte-stimulating hormone (MSH) receptor in bovine coat color determination. Mammalian Genome, 6(9), 636–639. https://doi.org/10.1007/BF00352398 

LEA-White Farms. (n.d.). Color in Highland cattle. Retrieved January 28, 2026, from https://www.leawhitehighlandcattle.com/general-5 

LEA-White Farms. (n.d.). Bulls and offspring. Retrieved January 28, 2026, from https://www.leawhitehighlandcattle.com/bulls-and-offspring 

Littlejohn, R. P., et al. (2012). Pigmentation genetics of cattle. Animal Genetics, 43(1), 1–10. https://doi.org/10.1111/j.1365-2052.2011.02239.x 

Olson, T. A. (1999). Genetics of colour variation. Proceedings of the British Society of Animal Science, 23–29. 

Sponenberg, D. P. (2003). Equine color genetics (3rd ed.). Iowa State Press. 

Sponenberg, D. P., & Rothschild, M. F. (2001). Genetics of coat colour and hair texture. Cattle Breeding and Genetics Journal. 

University of California, Davis Veterinary Genetics Laboratory. (n.d.). Coat color testing in cattle. https://vgl.ucdavis.edu