Low abundance, high ubiquity taxa.

<p>This figure helps the observer to comprehend the relationship between abundance and ubiquity when defining a core microbiome. As one would expect, increasing the abundance threshold for defining whether a sample contains a particular taxon would reduce the percentage of samples (ubiquity) that would contain it. The lines that are presented refer to all taxa in the stool samples that are in more than 97.5% of the samples with an abundance cutoff of 0.05%. The taxon <i>Bacteroides</i> (red) is both relatively highly abundant and highly ubiquitous, so its fall off is less steep than the Clostridales shown.</p>