Fig. 2

Sample selection and experimental design for the two-sample titration 16S rRNA marker-gene-survey assessment dataset. a Pre- and post-exposure (PRE and POST) samples from five vaccine trial participants were selected based on Escherichia coli abundance measured using qPCR and 454 16S rRNA sequencing (454-NGS), data from Pop et al. [22]. Counts represent normalized relative abundance values for 454-NGS and copies of the heat-labile toxin gene per microliter, a marker gene for ETEC, for qPCR. PRE and POST samples are indicated with orange and green data points, respectively. Gray points are other samples from the vaccine trial time series. b Proportion of DNA from PRE and POST samples in titration series samples. PRE samples were titrated into POST samples following a log₂ dilution series. The NA titration factor represents the unmixed PRE sample. c PRE and POST samples from the five vaccine trial participants, subjects, were used to generate independent two-sample titration series. Four replicate PCRs were performed for each of the 45 samples, 7 titrations + 2 unmixed samples times 5 subjects, resulting in 190 PCRs