How does conjugation work?

Fig. 14.9

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Fig b

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What question did Tatum and Lederberg set out to answer? What led them to expect bacteria exchanged genetic information? Why did he pick the bacteria (E. coli) he used as starting material?

Why did Lederberg want to use multiple mutations? How did he get multiple mutations? What kind of mutations are made by X-rays And what kind by UV light?

B- M- P+ T+ and B+ M+ P- T- culture together Get 10 2 /10 9 prototrophs: B+ M+ P+ T+ What did Lederberg do to get recombinants?

Other possible explanations Cross feeding (syntropism) limiting dilution plating Transformation mixed culture media with each parental type

After conjugation what are the most common products? What do the rare classes represent? Did recombination occur in both directions?

Did all possible parental combinations lead to prototrophs? What must E. coli K12 have for Lederberg’s Experiments to have worked? Why is frequency of prototrophs so low?

Is this recombination mechanism equivalent to sexual recombination in eukaryotes?