Characterization of Phage Fitness through Single-Phage Assays A thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Science with Honors in the Computational Biology concentration of Brown University

Bacteriophage (phage) life history traits include lag time, and burst size. To characterize the distributions of these traits, individual φX174 virions were isolated in each sample and combined with E. coli at the start time. The number of phage present in each sample was assayed at various time-points—samples in which many phage were observed were denoted bursts. No bursts were observed before a certain time-point, and the proportion of phage that burst was seen to increase over time, which was modeled with a cumulative exponential distribution. The size of bursts was seen to fit a normal distribution, and that distribution was shown to depend on time. The distributions that model burst size and lag time can be used to determine the variance in these two traits, which has significant implications for modeling phage evolution and the characterization of phage adaptation.