Overo (Fr)

Overo, or Frame Overo,  is a white marking pattern that is best known for its jagged edges and unfortunately, its lethal possibility. Frame Overo horses all have the genes “Frn” due to overo being lethal in the homozygous form (FrFr). In real life, it is suggested horses be tested for frame overo before breeding as the phenotype of the gene sometimes is not clearly noticeable. Breeding two frame overo horses together is also advised against as there is a 25% chance for a overo lethal white foal, meaning, the foal is FrFr and will not live.

In Horse Fable even lethal genes are possible and produce no foals. Any two frame overo horses (Frn) when bred together have a 25% chance of producing the lethal combo (FrFr) and thus, no foal.