Hmm... are you sure she was bred to a yellow male(and only a yellow male)? From a genetic standpoint that should be pretty durn impossible. In labradors, the yellow coat color is recessive.
There are 2 basic genes that affect coat color in Labs. The first gene determines if the pup is Black or Chocolate (BB or Bb = Black, bb = chocolate). There is a second gene that determines yellow vs non-yellow (ee = yellow, Ee or EE = Chocolate or Black). So in order to be yellow, your dog has to be either Bbee or BBee... and therefore can only pass on yellow alleles. In order for her to have puppies that express chocolate (bbEe), she would have to be bred to a chocolate male or a black male carrying a chocolate recessive.
Bottom line, yellow bred to yellow should produce all yellow puppies. So I'm afraid if she were my dog, and I had paid for a yellow stud... I'd be requesting a DNA test.
On the nose theory, a yellow lab with a brown nose and light eyes is called a dudley. These dogs are homozygous recessive for both genes (bbee), and is undesirable according to the breed standard.
There are 2 basic genes that affect coat color in Labs. The first gene determines if the pup is Black or Chocolate (BB or Bb = Black, bb = chocolate). There is a second gene that determines yellow vs non-yellow (ee = yellow, Ee or EE = Chocolate or Black). So in order to be yellow, your dog has to be either Bbee or BBee... and therefore can only pass on yellow alleles. In order for her to have puppies that express chocolate (bbEe), she would have to be bred to a chocolate male or a black male carrying a chocolate recessive.
Bottom line, yellow bred to yellow should produce all yellow puppies. So I'm afraid if she were my dog, and I had paid for a yellow stud... I'd be requesting a DNA test.
On the nose theory, a yellow lab with a brown nose and light eyes is called a dudley. These dogs are homozygous recessive for both genes (bbee), and is undesirable according to the breed standard.