The VGL recently identified the mutation responsible for the black phenotype in the impala and has developed a test for this mutation. The test makes it possible to identify carriers / splits for the black variant. Black is carried as a recessive mutation and carriers do not express black in the coat, but appear as normal red impala. The direct test provides the breeder with the guarantee that their breeding stock carries the mutation which makes it possible to select high quality carriers from a wider genetic pool at a lower cost. Red offspring from 2 carrier matings can be tested and the wild types (non carriers) removed from the breeding herd. This direct test will also make it possible to determine the prevalence of the black mutation in the wild impala population which will have direct implications on the role and management of these colour variants in the natural population.
The following figure shows the inheritance of a recessive mutation when two carriers (splits) are mated. From such a mating there is a 25% chance of producing the colour variant, a 50% chance of producing another carrier and 25% chance of producing a wild type animal, which does not carry the mutation at all.
The results of the black impala test are provided as follows:
BB: Carries 2 copies of the black mutation and is black
BW: Carries 1 copy of the black mutation (is a black split)
WW: Does not carry the black mutation and is a wild type or red impala