Using Crosses to Group Mutations

A complementation test uses a simple cross to find out whether two mutations are in the same gene or in different genes. It helps show how mutations are arranged on chromosomes. Edward Lewis first performed this test in the 1940s while studying fruit flies.

To do the test, organisms heterozygous ...

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 wi...