The black coat color in Pembroke Welsh Corgis is caused by a recessive gene called "K". Dogs with two copies of this gene (KK) will be black, while dogs with one copy of the gene (Kk) will be red or sable (a mix of red and black hairs). Dogs that completely lack the K gene (kk) will be fawn.
Breeding:
Black Pembroke Welsh Corgis are the result of selective breeding by breeders who prefer this coat color. Breeders can produce black puppies by breeding together two black corgis or by breeding a black corgi with a red or sable corgi who carries the recessive black gene.
Prevalence:
Black is a relatively rare coat color in Pembroke Welsh Corgis, making up only about 5% of the population. Red and sable are the most common coat colors, followed by tricolor (black, red, and white) and blue merle.
Health:
There is no evidence to suggest that black Pembroke Welsh Corgis are any more or less healthy than corgis of other coat colors. However, some studies have suggested that black dogs may be more susceptible to certain skin conditions, such as dermatitis and alopecia.