Chapter 6, Problem 1PDQ

HOW DO WE KNOW?

In this chapter, we have focused on genetic systems present in bacteria and on the viruses that use bacteria as hosts (bacteriophages). In particular, we discussed mechanisms by which bacteria and their phages undergo genetic recombination, which allows geneticists to map bacterial and bacteriophage chromosomes. In the process, we found many opportunities to consider how this information was acquired. From the explanations given in the chapter, what answers would you propose to the following questions?

1. (a) How do we know that genes exist in bacteria and bacteriophages?
2. (b) How do we know that bacteria undergo genetic recombination, allowing the transfer of genes from one organism to another?
3. (c) How do we know whether or not genetic recombination between bacteria involves cell-to-cell contact?
4. (d) How do we know that bacteriophages recombine genetic material through transduction and that cell-to-cell contact is not essential for transduction to occur?
5. (e) How do we know that intergenic exchange occurs in bacteriophages?
6. (f) How do we know that in bacteriophage T4 the rII locus is subdivided into two regions, or cistrons?