Labrador Retriever

　　Labrador Retrievers have three colors: black, yellow, and chocolate.

　　Any other colors or color combinations are disqualified. Small white patches on the chest are allowed but not ideal. White hairs caused by aging or scars should not be mistaken for spots. Black: entirely black, black with spots or black with brown markings are disqualified. Yellow: yellow ranges from fox red to pale cheese color, with color variations on ears, back, and underside.

　　Chocolate: allowed from light chocolate to dark chocolate. Chocolate with spots or brown markings is disqualified.

　　According to research data, Labrador chocolate and black colors are dominant genes, while yellow is a recessive gene. Using examples: chocolate is represented with bb, black with BB, black and chocolate with Bb, yellow with E, and yellow and chocolate with e.

　　Thus the following combinations appear:

　　Black Labradors carry the following gene combinations: BBEE, BBEe, BbEE, BbEe; chocolate carries bbEE, bbEe; yellow carries BBee, Bbee. There is also a type of dog called Dudley, with genotype bbee, showing yellow fur, brown nose, and amber eyes. According to the American AKC standard, this is disqualified, but genetically it is a normal dog born from mating chocolate and yellow Labradors. However, logically, two chocolate Labradors cannot produce a black puppy. Strange! The mating combinations for producing chocolate puppies are black and black, black and yellow, black and chocolate, yellow and chocolate. Below are calculations showing the probabilities of puppy colors from various parental color pairings: (due to genetic mixing in past generations, some puppies may not match the colors and probabilities shown here, which requires further study)

Puppy color Chocolate Black Yellow

Parental colors

Black + Yellow 9.375% 65.625% 25%

Black + Black 5.85938% 87.89063% 6.25%

Black + Chocolate 23.4375% 70.3125% 6.25%

Chocolate + Chocolate 93.75% 0 6.25%

Yellow + Yellow 0 0 100%

Yellow + Chocolate 37.5% 37.5% 25%