Bivariate plot of V region specific average number of reads compared to hypothetical V region length.

The length of each V region-specific amplicon mapping to the Escherichia coli 16S rRNA gene that was targeted by each group of forward and reverse primers in the Ion 16STM Metagenomics Kit was calculated for each V region(s). Spearman rank correlation was computed to assess the relationship between amplicon length (x-axis) and the average number of reads (y-axis) that mapped to targeted V-region(s). Amplicon length was not associated with the total number of reads that mapped to a targeted V-region A. CutPrimers (r = -0.13, p = .811) or B. Cutadapt (r = -0.11, p = .831). (PNG)