Like it is written in FCI standard, flat coated retrievers comes in two colours - solid black and solid liver. But furthermore exists, even if not approved by the standard, a third colour: the yellow. The DNA test for colours can be executed on blood or in the mouth; in this way we are able to notice the transmission of this "unwelcome" colour at the puppies.   Two sets of genes (E, b), not one, check the colouring of the cloak of the flat coated. A set (E or e) checks together be the dark colour (black and liver) or to be the clear one (yellow). Simplifying, the possibilities for black flat coated are: BBEE (pure black with only black talent) BbEE (black with liver talent) BBEe (black with yellow talent) BbEe (black with liver and yellow talent) The possibilities for yellow flat coated are: BBee, Bbee, bbee At last, the possibilities for liver flat coated are: bbEE (liver dog) bbEe (liver with yellow talent)   In breeding remember that the puppiess will take one E, e (capital or tiny) from mother and one from the dad, as like that as one B, b (capital or tiny) from the mother and one from the dad to have the complete genetic code. If both parents are BbEe (black) it is possible that puppies will be of all three colours. Two liver will only be able to transmit the bb combination to their children, so two livers will never produced black puppies. “E” extends the dark pigments (black and liver) also in the cloak, "e" reduces the dark pigments from the cloak. Therefore "ee" is a yellow dog. "B" give the possibility of having black pigment, as like that as "b" give the possibility of having the liver pigment. Therefore, Bbee is a yellow dog which has black pigment, but the liver pigment preserves in his genes. Please remember that "B" represents only the possibility of having black or liver pigment. The bbee is an interesting case, is a yellow flat coated with the pigmentation like liver flat coated (nose, surround eyes and surround mouth).   For better view in the GENOTYPE OF FLAT COATED RETRIEVERS:   BBEE BBEe BbEE BbEe BBee Bbee bbee bbEE bbEe BBEE All Black All Black All Black All Black All Black All Black All Black All Black All Black BBEe All Black ¾ Black ¼ Yellow All Black ¾ Black ¼ Yellow ½ Black ½ Yellow ½ Black ½ Yellow ½ Black ½ Yellow All Black ¾ Black ¼ Yellow BbEE All Black All Black ¾ Black ¼ Liver ¾ Black ¼ Liver All Black ¾ Black ¼ Liver ½ Black ½ Liver ½ Black ½ Liver ½ Black ½ Liver BbEe All Black ¾ Black ¼ Yellow ¾ Black ¼ Liver 9/16 Black ¼ Yellow 3/16 Liver ½ Black ½ Yellow 3/8 Black ½ Yellow 1/8 Liver ¼ Black ½ Yellow ¼ Liver ½ Black ½ Liver 3/8 Black ¼ Yellow 3/8 Liver BBee All Black ½ Black ½ Yellow All Black ½ Black ½ Yellow All Yellow All Yellow All Yellow All Black ½ Black ½ Yellow Bbee All Black ½ Black ½ Yellow ¾ Black ¼ Liver 3/8 Black ½ Yellow 1/8 Liver All Yellow All Yellow All Yellow ½ Black ½ Liver ¼ Black ½ Yellow ¼ Liver bbee All Black ½ Black ½ Yellow ½ Black ½ Liver ¼ Black ½ Yellow ¼ Liver All Yellow All Yellow All Yellow All Liver ½ Liver ½ Yellow bbEE All Black All Black ½ Black ½ Liver ½ Black ½ Liver All Black ½ Black ½ Liver All liver All Liver All Liver bbEe All Black ¾ Black ¼ Yellow ½ Black ½ Liver 3/8 Black ¼ Yellow 3/8 Liver ½ Black ½ Yellow ¼ Black ½ Yellow ¼ Liver ½ Liver ½ Yellow All Liver ¾ Liver ¼ Yellow