Fig. 1: Quantification of mispackaging of host DNA during infection of Prochlorococcus MED4 by three cyanophages.

a Electron micrograph of the three cyanophages infecting Prochlorococcus MED4 used in this study. The scale bar is 50 nm. b Cartoon illustrating the experimental method. A cyanophage infection typically results in the production of a small fraction of cyanophage capsids having mispackaged host DNA, represented in red. c Detection of host DNA mispackaging inside cyanophage capsids under standard laboratory conditions, at a constant light intensity of 45 µmol Q m⁻² s⁻¹ (see ‘Materials and methods’ for details). The frequency of a gene mispackaging during infection is expressed in gene copies per million phages. Each symbol is the mean of three parallel infections for a given locus (Table 1). The colored dotted line is the mean value of all loci and all replicates. The three colors for the different phage are arbitrary—for ease of visualization. d Impact of growth light intensity on mispackaging during infection. The data 45 µmol Q m⁻² s⁻¹ are from (c), replotted for comparison. The dotted line at 0.5 gene copies per million phages marks the detection limit of the assay. The four colors for the different light intensities are arbitrary—for ease of visualization. The p values indicated between the lowest to highest light intensity samples were calculated by a Kruskal–Wallis test followed by a Dunn test. The graphs are replotted in Supplementary Fig. 1 to highlight locus to locus variations.