Two strains of E. coli, A and B, are inoculated into a chemostat in equal proportions. After one generation, the frequency of strain B is 20%. Calculate the fitness of strain B relative to strain A.
The genotype with the highest reproductive ability is given a fitness value of 1.0. The fitness values of the other genotypes are assigned values relative to this 1.0 value. In our case fitness of strain A is 1.0 and fitness of strain B is 0.2. It means that all bacteria of strain A will survive, and only 20 percent of strain B bacteria will survive.