 A single, incomplete dominant gene ("Lp") controls the presence of leopard-spotting in horses.A dominant gene requires only a single copy to produce an affected phenotype; an incomplete dominant gene produces a different result depending on whether one or two copies are present.A horse's genotype may be "lp/lp" (homozygous recessive), "Lp/lp" (heterozygous), or "Lp/Lp" (homozygous dominant).