It should be observed that it is recognised that Merle can be a genetic trait that functions in a very diluting fashion. As such when breeding Merle it is very advised that it's bred to other non-Merles due to hazard of double dilution. Some breeders have documented good results http://merlepitbullpuppiesforsal36913.dbblog.net/22989236/5-essential-elements-for-merle-pitbull-puppies-for-sale