CISTRANS TEST

cis-trans test: translation

The complementation test with two or more interacting genes placed in cis and in trans relationships to each other. A double mutant genome is used in the cis test made from the two single mutant genomes used in the trans test by recombination. If the wild type phenotype is restored by both cis and trans arrangements it is concluded that the two mutations are in different genes and hence that the phenotype is determined by more than one gene. If the trans test is negative and the cis positive this means that the two mutations are in the same gene. If both tests are negative then at least one of the mutations must be dominant. Thus the double test provides a means of fine mapping of genes.