Canine Coat and Nose Color Testing

Presence of black, chocolate (brown), yellow, and diluted coat colors and black and brown nose.
Labrador Retrievers commonly occur in three main colors: black, chocolate or brown, and yellow as shown in the photo above. Black or chocolate Labs always have nose leather and pads the same color as their coat. However yellow Labs may have black or brown nose and pads, depending on their alleles at the B locus. Dogs with brown noses are not shown in some countries/associations. Owners wishing to know about only these main colors should order a DNA test for the E and B locus.

A small proportion of Labrador Retrievers have an allele at the D of dilute locus that causes black Labs to be blue or gray and brown labs to be a pale grayish brown. Such dilute dogs have two d alleles at this locus. Dogs with a Dd genetic makeup do not have a detectable change in their coat color and therefore DNA testing is necessary to detect these  carriers or  heterozygotes of the dilute allele. These dilute colored dogs are not shown in many countries/associations. There is also a wide variation in shades of yellow in Labs from golden to pale. However the gene causing this variation has not yet been found. Research continues to identify this gene. Yellow Labs may carry the dilute allele in homozygous (dd) or heterozygous (Dd) states with no obvious effect on shade of yellow. There is also benefit from DNA testing of yellow Labs for breeders who are interested in knowing if the dilute allele occurs in their breeding animals.