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COLOUR GENETICS - K locus

The K locus (BLACK) is a gene series identified only in recent years (2003) according to emerging genetic research. This locus is where dominant black appears to belong as well as brindle. There are at least 3 alleles in this series but there may be more. K controls dominant dark pigment. Full dominant black completely dominates all expression on the A locus. However it is still has to pay attention to the whims of the E locus. If no dark pigment is made [ee], then it has none to deposit. The order of dominance is [K] > [kbr] > [k]. When just looking at letter designations, this one can be a bit confusing as the upper case K and lower case k may look very similar.

Remember that E can be brown as well as black. Although only the black variations are shown here, all the same possibilities exist in brown.

dominant black [ K ] This is the most dominant allele and deposits intense dark colour all over. It overides the directions on A for creating colour patterns and allows no expression at all from the A locus.
Phenotype - dominant black coat
Genotype - [ KK ] or [ Kkbr ] or [ Kk ]

dog displays brindle [kbr] The brindle allele deposits dark colour in a tiger striped pattern across the body. Similar to dominant black, brindle is generally considered dominant over all A patterns.
Genotype - dog displays brindle
Phenotype - [ kbrkbr ] or [ kbrk ]

dog displays dark colour [ kk ] : recessive [k] is a normal expression of dark, some call it recessive black expression. It does not dominate at all, thereby allowing the full expression of the A series which allows us to see many Havanese patterns.
Phenotype - dog displays dark coat colour
Genotype - [ kk ]