Fig. 1: Diversity in tetracycline-inactivating enzyme sequence corresponds to microbial habitat of origin.

a Sixty-nine tetracycline inactivators were identified from tetracycline and tigecycline selections of diverse metagenomic libraries. Genes selected for further analysis are indicated by gray dots at branch tips, and clinically implicated tet(X) variants are labeled. b Percent amino-acid identity heatmap indicates greater relative sequence diversity in the soil-derived set compared with the gut-derived set, but low identity between these two sets.