Should merle-to-merle breedings be done?
The merle color seems to be a trademark for Aussies. Non-merled Aussies are often mistaken for other breeds or mutts. However, the merle gene can be lethal to the uneducated breeder. The merle gene is an incomplete dominant gene – NOT a simple recessive. This gene is also completely separate from the color genes (black, red, tan, white, etc.). A dog with one merle gene and one solid gene will be a normal merle dog. A dog with two solid genes will be a solid (black or red). A dog with two merle genes will be a double-merle (a.k.a. lethal white, excessive white, or lethal merle). These double-merle dogs are usually predominantly white, and most often are deaf and/or blind, and can develop numerous other problems, such as organ failure, auto-immune disorders, and other disorders. The only way to get double-merle dogs is if two merles are bred together. If two merles are bred together, approximately 25% of the litter will be double- merles. Because of all the problems that double-merles ar
