A nutritionally defective E.coli strain grows only on medium containing thymine, whereas another nutritionally defective strain grows only on medium containing leucine. When these two strains are grown together, a few progeny are able to grow on minimal medium with neither leucine nor thymine. How can this result be explained?© BrainMass Inc. brainmass.com July 21, 2018, 2:18 am ad1c9bdddf
E. coli that can only grow on medium containing thymine are called thymine auxotrophs (thy-).
E. coli that can only grow on medium containing leucine are leucine auxotrophs (leu-).
Obviously, thy- is wild-type in all other genes; therefore, they are really thy-/leu+.
Same logic applies for the leucine auxotrophs. They are really thy+/leu-.
But how can a wild-type bacteria come out of ...
The solution discusses how an E.coli strain grow on a minimal medium with neither leucine nor thymine.