Merle

Merle is a genetic pattern in a dog's coat and alleles of the PMEL gene. It results in different colors and patterns and can affect any coats. The allele creates mottled patches of color in a solid or piebald coat, blue or odd-colored eyes, and can affect skin pigment as well. Two types of colored patches generally appear in a merle coat: brown/liver and black. Associated breeds include Carea Leonés, Australian Shepherds and Catahoula Leopard Dogs. Health issues are more typical and more severe when two merle-patterned dogs are bred together.