Do you think the competitive assay will provide right/wrong information in these cases?

Question

1.    Suppose you are doing the Competitive Assay to study the virulence of two mutants (mutant X and mutant Y) of a bacterial strain. Do you think the competitive assay will provide right/wrong information in these cases? Justify your answer.

i.        X is slow grower than Y

ii. Their growth rate is similar. However, X can produce the 'toxin T,' but Y cannot produce it. 'toxin T' is not essential for the bacteria's growth but responsible for producing a disease symptom

Answer 1

i. In this case, if mutant X is slower to divide and grow in pure culture, it may affect the virulence. Competition assays really evaluate fitness, so if it is slower to divide and replicate it will not produce as many bacteria and the infection would be slower.

ii. In this case the competition assay would not give you the right information. Assuming they had equal growth, they would be equally virulent. But if X can produce 'toxin T' and Y cannot, then X will cause a much more severe disease than Y. But you would not be able to determine the effects of 'toxin T' from the competition test.