Practice question

Evaluating six mutants producing three complementation groups involves pairwise trans tests clustering non-complementing mutants together into shared groups. Each group contains mutants allelic to each other but complementing members of other groups indicating distinct functional units. Number of groups equals number of genes whose inactivation yields same phenotype because each group corresponds to one cistron encoding one enzyme or structural component. Therefore six isolates falling into three groups reveal three distinct genes required for pathway not six independent loci, simplifying genetic architecture and indicating limited gene set.