Providing there is a Landseer in the background of a Newfoundland, they
may or may not have inherited the 'Landseer' gene.
Rosie is a black dog, but she is Landseer recessive, as her father was a
Landseer Newfoundland. We therefore know that she has received one
gene for black (from her mother) and one Landseer gene (from her father.)
A Newfoundland who carries the black gene will always be black, as the
black gene is dominant; the Landseer gene recessive.
In order for a Newfoundland to present with the Landseer colouring, they
must receive two Landseer genes; one from each parent. This means that
either the parents themselves must be Landseers or they must carry the
recessive Landseer gene.
For instance, our Navy is black and we knew that all of the pups in that
litter would be black even though the mother, Rosie, is Landseer
recessive. Because we bred Rosie to an all black male, who was not
Landseer recessive, all of the resulting puppies would have to be black,
although they could continue to carry the Landseer recessive gene.
We then bred Navy, who is a black Newfoundland, to Schooner who is also a
black Newfoundland. Because Navy's mother Rosie, was Landseer
recessive, Navy had a 50% chance of being Landseer recessive as well.
(She would have received the black gene from her father, and could have
received either the black gene from her mother or the Landseer gene from her
mother. (In her case, she received the Landseer gene.)