Fig. 4

Screening for TMA-producing genes in metagenomes of fecal samples (n = 154) from the Human Microbiome Project. On top the relative abundance of bacteria containing cutC/D (red) and cntA/B (blue) genes calculated as percentage of the total community indicated by the amount of reads matching the housekeeping gene rplB are shown. Samples are sorted along the horizontal axis according to their cutC/D abundances. Results of the gene-targeted metagenomic assembly method as a fraction of the BLAST (blastn) result are displayed as dark red (n = 6) and light blue (n = 3) for cutC/D and cntA/B, respectively (results for cutC/D exceeding those of blastn is shown in orange). Samples are sorted by descending quantity of cutC/D. Specific numeric labels give values exceeding the maxima of axis. Below associated taxonomic affiliations of respective gene communities are displayed. For CutC, reference sequences were subjected to complete-linkage clustering on the nucleotide level based on 90% identity, whereas cntA reference sequences were binned on the genus level. The EKRS cluster involves sequences from Enterobacter, Klebsiella, Raoultella, and Staphylococcus. Clostridium XIVa I, II, and III refer to distinct clusters composed of Clostridium XIVa strains. Asterisks highlight sequences derived from Clostridium XIVa strains. Samples where no genes encoding TMA production were detected (n = 38) are not shown