Complementation Tests

Sometimes, different mutations can produce the same phenotype, such as loss of coloration in bird feathers. Whether these mutations are in the same gene or in two different genes, can be determined using a complementation test.

Consider the breeding between two mutant chickens. If the same gene is mutated in both parents, the offspring will inherit the mutation and appear white.

On the other hand, if the offspring appears brown like the wild-type bird, then this would indicate that the parents had mutations in two different genes.

Although each parental gene had a mutation, they worked together to produce a wild-type phenotype. This phenomenon is called complementation.