Australian Shepherd Insights - Blog

Australian Shepherds are one of the breeds most commonly affected by the MDR1 mutation, with approximately 50% of the population carrying at least one copy of the gene.

I see it and hear it all the time: “I only want a blue merle with blue eyes or a red merle with green eyes.” Unfortunately, many people will overlook a superior puppy simply because it’s not the flashy merle in the litter. For those unfamiliar with the genetics, the merle pattern—caused by an incompletely dominant allele—can lead to complications if not handled properly, such as excessive white markings that may violate breed standards or increase health risks in certain comb