We will try to explain the Merle Gene the best we can for you:
There is no Blue Merle gene or Chocolate (Liver) Merle gene, there is only a Merle Gene. Merle is a dilution gene, it lightens whatever the color coat would have been. The lightening is not spread evenly over the coat, but leaves patches of undiluted color scattered over the dog's body. Merle gives a mottled or uneven speckled effect. Most breeds with Merle coats also typically have White markings (such as around the neck, under the belly, and on the legs), the White is separate from the Merle.
In addition to altering the base coat color, Merle also modifies eye color and the coloring on the nose and paw pads. The Merle gene can modify the dark pigment in the eyes, changing dark eyes to Blue or part of the eye to Blue. In none of these cases will the dogs vision be affect . Color on the nose and paw pads may be mottled Pink, Brown or Black. BLUE EYES ARE NOT CALLED MERLE EYES ON ANY BREED OF DOG. They are just Blue eyes. The eyes can be full Blue, Partial Blue, Speckled Blue or have Blue Flecks.
Below you can view Blue eyes.
A Phantom Merle, is a dog with a very small patch of Merle (sometimes called Cryptic for Merle), this is very rare.
Breeding Merle's: When breeding a Merle to a non Merle dog on average 50% of the pups should be Merle. Breeding a Merle to a Merle is not acceptable to most breeders. You should never cross two Merle's, as the results of doing so 25% of the litter will come out deaf and or blind (called a mismark - excessive White), 25% solid and 50% Merle. Statistics show that when you cross 2 Merle's you get the same amount of normal Merle pups (50%) as not crossing 2 Merle's, so why would you ever want to cross 2 Merle's and get deaf and blind ones, when the odds of getting viable Merle's are the same.