GENE20001 Lecture Notes - Lecture 15: Petri Dish, Cistron, Fine Structure
Document Summary
Coinfection creates a diploid state for the phage. This permits recombination between two phage dna molecules with different mutations. Crossover makes one genome a double wt and another a double mutant. The progeny phage will have different genotypes as the parents. Some will be wt and some will be double mutant. Plate progeny onto bacteria to score for recombinants and total phage. Need to plate so there are many more bacteria for each phage- low moi, to ensure that one phage infects one host. If more than one infect then there are two genomes which makes it hard for us to genotype the plaque so we cannot score. Mutants 1 and 2 can form plaques on e. coli b but not e. coli k. Wt recombinants should be able to grow on both. Progeny from this cross plated on e. coli b (permissive host) are counted to give total progeny.
