To How Many Cistrons Do These Mutations Belong

(a) To how many functional genes (cistrons) do these mutations belong?

(b) Which mutations belong to the same functional gene?


31. As a summer project, a microbiology student independently isolates two mutations in E. coli that are auxotrophic for glycine (gly-). The student wants to know whether these two mutants occur at the same cistron. Outline a procedure that the student could use to determine whether these two gly-mutations occur within the same cistron.

32. A group of genetics students mix two auxotrophic strains of bacteria: one is leu+ trp+ his- met- and the other is leu-trp-his+ met+. After mixing the two strains, they plate the bacteria on minimal medium and observe a few prototrophic colonies (leu+ trp+ his+ met+). They assume that some gene transfer has taken place between the two strains. How can they determine whether the transfer of genes is due to conjugation, transduction, or transformation?


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