The (G) gene acts on the base coat promoting progressive lightening throughout the horse's life until reaching very pale or completely white tones. This coat is based on Bay.
Typical Genetic Formula
E/_ A/_ G/n
Possible Genotype Variations
E/e A/a G/n
E/e A/a G/G
E/e A/A G/n
E/e A/A G/G
E/E A/a G/n
E/E A/a G/G
E/E A/A G/n
E/E A/A G/G
The Genetic Basis
For a horse to be born Gray 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.
- Gray does not skip generations. For this animal to be Gray, the sire or dam had to be Gray to provide the (Rn).
Understanding the Alleles
The horse Gray 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.
- G/ (Grey): Progressive graying. Epistatic — covers all other colors.
