It is very important to us as responsible breeders to do all that we can to raise healthy, sound puppies. For that reason we do not breed merle to merle. Many genetic abnormalities can occur and we are unwilling to allow them.

Here is a brief genetic explanation: A "mm" (mm = no merling) dog is of a normal color with no coat pattern. A "Mm" (Mm = merling) dog is merled. But an "MM" dog is considered a double dilute or double merle and has much more white that is normal for the breed. Double merle is also known as a lethal gene because when breeding merle to merle you may produce puppies that have hearing loss, vision problems including small or missing eyes, and possible infertility. In order to produce merle puppies with no defects (given that both sire and dam are genetically sound to begin with) it is safer to breed merle to a solid or non-merle dog. That is what we do here at Princess Petunia's Puppies. Merles bred to solid colors and non-merle dogs.

One parent has to be merle to get merle. It is a dominate gene that is not carried recessively. If the puppy has the gene for merle then it will express itself, even if only temporarily. A hidden or Phantom merle are merles that are not seen by the color pattern and should not be bred to a merle. Phantom merles have visible merle markings at birth, but as they mature the merle markings disappear. Even though the merle markings are not visible, these dogs are still merles and will produce merle offspring when bred. Genetically they are merle and can produce merle puppies.

It is important to understand that the merle gene is carried on a different gene series than colors are, therefore it is a pattern modifier of whatever color genes the dog is carrying, not a color. The best colors to get blue merles is black, black and tans, or dogs that have those colors in their pedigrees. Chocolate and blues are other good choices. Darker colors will produce the most vibrant colors. Tricolors seem to bring out the most colorful merles because of their red or fawn markings.

 Some breeders don't like to breed merle to brindle because they are both pattern modifying genes; however, they are two totally distinct and different patterns and a combination of the two patterns has never been reported. Merle dogs are very special and highly prized.

Any non merle, even if it has a merle parent can safely be bred to a merle, because merle is a dominant gene and is not carried . If you have two non-merles out of merle parents and grandparents and great grandparents, as long as neither is merle they cannot produce a merle because the gene is NOT CARRIED. If you end up with a merle puppy out of two apparent non-merle parents, then one of them has to be a hidden or phantom merle. The American Kennel Club recognizes merle as an acceptable coat marking for chihuahuas.