Fig. 4
DNA contaminants introduced by library preparation. a Quantity of contaminating DNA in each kit. *p < 0.05, Wilcoxon tests. b The proportion of remaining contaminants (out of all contaminating reads), after filtering components below certain relative abundances. Dotted lines indicate relative abundances of the most abundant contaminating genera in libraries with each input amount, where the proportion reaches 0. c PCoA plot based on JSD of contaminating compositions. R2 and p values from PERMANOVA are shown. Circles indicate 95% confidence. d JSD between contaminating compositions of experimental replicates. e Venn diagram of core contaminating genera, which had relative abundances higher than 0.1% in at least half of the libraries for each kit. The proportion of core contaminating genera in all microbial contaminants for each kit is shown in brackets. f Heatmap showing 32 dominant contaminants, which had relative abundances higher than 1% in at least half of the libraries for each kit. Common niches of the microbes are indicated on the left. In a, c, and f, libraries with 0.5–50 pg input are shown whereas all libraries are used in the rest panels