Question

Three autotrophic strains of E. coli (#1-3) of genotype a(-)b(+) are mixed in all possible combinations with three auxotrophic strains (#4-6) of genotype a(+)b(-), and subsequently plated on basal media.

A few recombinants form colonies when the following strains are mixed: 2+4 and 3+6

Many recombinants form colonies when the following strains are mixed: 1+6 and 2+5

All other combinations produce no surviving recombinants on basal media.

What are the mating types (F+, F-, Hfr) of all six strands?

Three auxotrophic strains of E. coli (#1-3) of genotype a(-)b(+) are mixed in all possible combinations with three auxotrophic strains (#4-6) of genotype a(+)b(-), and subsequently plated on basal media. 1. A few recombinants form colonies when the following strains are mixed: 2+4 and 3+6 Many recombinants form colonies when the following strains are mixed: 1-t6 and 2- All other combinations produce no surviving recombinants on basal media. What are the mating types (F+, F-, HFr) of all six strains? (6 Points)

Answer 1

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