"White Collie in a Landscape", by Sir Edwin Landseer, 1829.
(image source: artvalue.com)
Landseer was a noted artist who is probably best known for his dog paintings - the black and white newfoundland is named Landseer in his honor. His collie paintings are wonderful, and show what the original shepherd's dog looked like. They contrast with some later artists such as Elsley and Barber, whose dogs are plush, well-groomed Victorian gentlemen, not workmanlike shepherd dogs.
I'd like to know more about this little guy. Is he "white", or is he homozygous merle? His eyes appear pale, and his nose has a pinkish hue. He has one spot of color on the base of his tail. The dog also appears to be uncomfortable in this situation - in spite of the sheep in the distance, he looks like he'd rather be somewhere else. Landseer was an expert in portraying the subtleties of dog body language. Something about this white canine seems to be amiss - he's leaning back slightly, one paw is raised, his lip line is tense, and his gaze is avoiding the viewer. Perhaps his vision is impaired, or perhaps he's deaf.
"Merle" has a unique etymology. In Scotland, it It means blackbird in French, as in the idiom "le merle blanc", or the white blackbird. The phrase means "the impossible thing" or "the thing which should not be". An English equivalent would be to call something "as rare as hens' teeth".
White blackbirds do exist, though, just like homozygous merle (and unlike hens' teeth), although the color isn't connected with any impairment aside from making the bird more visible to predators. It's leucistic, not albinistic; the bird has black eyes and some pigment. The color may be vareigated, resembling a merle dog, or solid white. Early merle collies were also referred to as "marled", "marbled", "calico", and "tortoiseshell".
Is the blackbird connection the reason why merle became associated with dogs? Perhaps early shepherds, not fully understanding merle genetics, saw the resemblance between the birds and the dogs. The birds could be black, varicolored, or solid white. So could the dogs. The multicolored and white dogs were much rarer than the black (at one time, the most common color for collies). Or maybe the use of merle is related to the French "merle blanc". A white dog, especially one who wasn't able to work effectively, would indeed be The Thing Which Should Not Be.
