Fig. 1.

Relationships between putative streptococcal phage and their hosts. Relative abundances of Streptococcus species (black boxes) and putative streptococcal phage (white boxes) in the saliva of four subjects at 11 different time points over 60 days. Relative abundances of streptococci were determined based on the number of V1–V2 segment-16S rRNA reads assigned to the genus Streptococcus, and putative streptococcal phage assignments were determined based on BLASTX best hits to streptococcal phage. The percentage of all 16S rRNA reads assigned to streptococci are shown on the left y-axis, and the percentage of phage contigs assigned to streptococcal phage are shown on the right y-axis. The x-axis shows the day each subject was sampled. AM represents morning time points, NN represents noon time points, and PM represents evening time points. Panels a and b show subjects 1 and 2, and demonstrate an inverse relationship between the relative abundances of streptococcal species and their phage. Panels c and d show subjects 3 and 4 and demonstrate direct relationships.