Fig. 6

Decontam frequency distribution plots distinguish contaminants from non-contaminants. A frequency distribution plot generated from samples with varying DNA concentration indicates whether a particular sequence fits the Decontam contaminant (red line) or non-contaminant (black stippled line) model. The first four plots represent the top four operational taxonomic units (OTUs) observed in negative control samples (NCS): OTU 759061 is assigned to the family Enterobacteriaceae; OTU 4389128 is assigned to a genus within the class ML635J-21; OTU 437105 and OTU New. Reference OTU 133 are both assigned to the genus Ralstonia. The final plot represents the Streptococcus OTU 1082539 that most likely is not a contaminant, although present among the top 20 OTUs found in NCS. Its frequency distribution pattern more closely fits the Decontam non-contaminant model in contrast to the others