I thought it might be fun to explore coat patterns in dogs, mainly my favorite of all patterns… The MERLE!
If asked my favorite color for dogs I say Blue! If asked my favorite coat pattern it has got to be the merle. I love unusual things. From flowers to clouds…
I have collected some photographs of dogs with this type of coat pattern, starting with my Maggie Mae RIP. She brought me 22 years of pure joy.
She was an Australian Shepherd mixed with a Shiba Inu. This made her the perfect mini aussie, before there was even such a thing.
The merle pattern is produced when a dog has a single copy of the M< allele. All merle dogs have the genotype Mm — meaning they have one allele for merle and one allele for non-merle. All non-merles are mm. If you breed a merle (Mm) to a non-merle (mm) you will on average produce a litter in which a half of the puppies get the M allele so are Mm (merle) and half get the non-merle allele so are mm.
But if you breed two merles together (Mm X Mm) you will produce on average a quarter mm (non-merle), a half Mm (merle) and a quarter MM (double-merle; also called double-dapple). And double merles don’t look like merles. Instead, they’re mostly white with merle patches. But the main reason you want to avoid producing MM dogs is that they often have visual and auditory problems.
Was that confusing enough?!!
You cannot breed two merles together. When this happens it is called a double merle.
In a study of several merle breeds, merles with one copy of the M allele had a rate of 2.7 percent deaf in one ear and 0.9 percent deaf in both ears; double-merles had a rate of 10 percent deaf in one ear and 15 percent deaf in both ears.