Merle is a pattern in a
dog's
coat, "Merle" comes in different colors and patterns. Some have blue patches through out and are considered blue "Merle", same with red and some are also chocolate, although some describe Merle as only a "pattern" New research has been hard to rule out "Merle" as also a color modifier because of the unique colors associated with Merle that do not test as in normal dna colors. A dilute black (BB or Bb) dog is generally known as blue, but in Merle it does not test BB or Bb but still is a blue dilute from the "Merle" gene The Merle gene creates mottled patches of color in a solid or
piebald coat, blue or
odd-colored eyes, and can affect skin pigment as well. Health issues are more typical and more severe when two merles are bred together, so it is recommended that a merle be bred to a dog with a solid coat color only.