Fig. 1

Human gut microbiome bacterial sequence reads are misattributed to eukaryotes. a Metagenomic sequencing reads were simulated from 971 species total from all major phyla in human stool (2 million reads per species) and aligned to all microbial eukaryotic genomes used to develop EukDetect. Even after stringent filtering (see “Methods”), many species have thousands of reads aligning to eukaryotic genomes, which would lead to false detection of eukaryotes in samples with only bacteria. b Amount of eukaryotic genome sequence aligned by simulated bacterial reads in 1367 eukaryotic genomes. c Taxonomic distribution of eukaryotes in whole-genome database. Dark blue indicates eukaryotic genomes where bacterial reads aligned