Treatment-based rarefaction curves of 16S rRNA gene libraries. The rarefaction curves from IN (pink), OUT (green) and IR (black) animals were generated by plotting the number of phylotypes (OTUs; defined at 99% sequence identity) against the number of clones sequenced. The shape of the curves of observed phylotype richness indicates a trend of diminishing chance of finding new phylotypes as sampling continues.
Mulder et al. BMC Biology 2009 7:79 doi:10.1186/1741-7007-7-79