"Decimation of Scottish Highlander culture was the death knell to the Highland Collie strain. Fortunately for us, however, before the strain’s demise they contributed to the development of several modern-day herding dog breeds, including Great Britain’s Border Collie (when crossed with the working sheepdogs of the Anglo-Scot Borders counties) and modern show Collie (when crossed with Lowland Collies and Queen Alexandra’s Russian Wolfhounds). Highland Collies who immigrated to North America were absorbed into the English Shepherd (primarily on Eastern and Midwestern farms) and the Australian Shepherd (primarily on Western ranches)."

An answer to "Why don't English Shepherds Come in Merle?"

"As things stand with traditional dog breeding, the competitive struggle for individual excellence has harmful consequences for breed populations. What is needed is for breeders to think in population terms, to look at each breed genetically as a population and each breeder involved with that particular population as a conservator of that breed in partnership with others..."

"...dog breeders have historically gone to great lengths to produce dogs with unique phenotypic characteristics desirable to potential pet buyers. While most of these characteristics are simple, mendelian genetic traits without health concerns, some desirable and interesting traits such as the merle coat color pattern are unique to domestic animals and bring with them a complexity and potential health concerns that veterinarians should be aware of in their goal of facilitating canine health and wellbeing."

"Gregor Mendel was an Austrian monk who, through his scientific work with pea plants, became known as the father of genetics. Mendel illustrated that genes come in pairs with one inherited from each parent. This may sound like a simple gardening experiment, but from pea plants to dogs to humans, genetics is complex..."