The (Rn) gene acts on the base coat by distributing white hairs throughout the body, giving it a roan appearance. The head and legs retain the original base color tones. This coat is based on Bay.
Typical Genetic Formula
E/_ A/_ Rn/n
Possible Genotype Variations
E/e A/a Rn/n
E/e A/a Rn/Rn
E/e A/A Rn/n
E/e A/A Rn/Rn
E/E A/a Rn/n
E/E A/a Rn/Rn
E/E A/A Rn/n
E/E A/A Rn/Rn
The Genetic Basis
For a horse to be born Roan Bay, it must receive the following combination from its parents:
- Its ability to express or produce black pigment indicates it received the dominant E allele from at least one parent.
- Since the Roan gene is dominant, at least one parent was necessarily Roan (Rn).
Understanding the Alleles
The horse Roan Bay has a specific combination of alleles. Below, we explain each genetic component that forms this coat:
- A/ (Agouti): The Agouti gene, when active (with E present), restricts black pigment to the extremities. Carried with no visual effect in e/e animals.
- Rn/ (Roan): aaaaaaaaaaaaaaaa
