Chapter 6

In Bacillus subtilis, linkage analysis of two mutant genes affecting the synthesis of two amino acids, tryptophan $\left(\mathrm{tr}{p}_2\right)$ and tyrosine $\left({\mathrm{tyr}}_1^{-}\right),$ was performed using transformation. Bxamine the following data and draw all possible conclusions regarding linkage. What is the purpose of Part B of the experiment? [Reference: E. Nester, M. Schafer, and J. Lederberg (1963).]

A plaque assay is performed beginning with $1\mathrm{mL}$ of a solution containing bacteriophages. This solution is serially diluted three times by combining 0.1 mL of each sequential dilution with $9.9\mathrm{mL}$ of liquid medium. Then 0.1 mL of the final dilution is plated in the plaque assay and yields 17 plaques. What is the initial density of bacteriophages in the original 1 mL?