In the 20th century the solid black coloration became more popular and supplanted the bi-colored animals, so much so that in the 1930s a concerted effort was made to recreate the dogs seen in the paintings of Landseer. The efforts of these breeders resulted in the Landseer breed. In Great Britain and North America Landseer colored dogs are considered a variety of the Newfoundland breed, but in 1976 a separate breed club for Landseer colored dogs was created in Germany. Similar clubs soon followed in Belgium and Holland, and they are now considered a separate breed in continental Europe with separate Fédération Cynologique Internationale recognition.
The Landseer's black and white coloration arises from the recessive piebald color allele found in Newfoundlands, the piebald coloration is a recessive trait so a single litter can have both Landseer and solid-colored puppies, depending on the genotype of the parents. With this split in recognition gradual differences in appearance began to appear between the two forms, the European form is taller with longer legs and less bulk, and a longer more tapered head, its coat is said to be curlier whilst the Newfoundland's is said to be wavier.
A study in 2015 found a special gene in Landseers with muscle dystrophy called COL6A1 that could provide researchers with important information that can lead to a vaccine for the disease overall.