Allelic or Non-Allelic? Complementation Studies With Bacteriophage T4 rII Mutations

 

Susan J. Karcher

Tested Studies in Laboratory Teaching, 2003, Volume 24

Abstract

An easy-to-perform exercise to demonstrate complementation is presented. Complementation tests are used to determine whether mutations affecting the same phenotype are within the same gene (allelic) or in different genes (non-allelic). In this exercise, mutations in the rII locus of bacteriophage T4 are studied. Host E. coli bacteria are co-infected with different T4 mutant phage. If two mutations are in different genes, the mutations will complement each other allowing phage to grow and produce a plaque on top agar. If two mutations are in the same gene, the mutations will not complement each other and phage will not grow to form a plaque. This miniworkshop presents the rII locus of T4 that provides a simple system for students to test complementation.

Keywords:  E. coli, complementation, phage

Louisiana State University (2002)