(a) FACS dot plots of in vitro conjugations of mouse gut bacteria and EcGT2 donors with vector libraries pGT-L1, L3, and L7. This experiment was performed 3 times, with similar results. Green boxes define the sorted GFP+mCherry– transconjugant populations. (b) 16S taxonomic classification of in vitro GFP+mCherry– transconjugants of pGT-L1, L3, and L7 enriched by FACS. Relative abundance of each OTU in the unsorted population is shown in the grayscale heat map, and fold enrichment for transconjugants of each OTU is shown in the orange heat map, with annotated taxonomic identities. Bracketed values indicate confidence of taxonomic assignment by RDP Classifier. Genera with successfully cultivated isolates are denoted by stars. Each column represents FACS-enriched transconjugants from one conjugation. (c) Comparison of OTUs shared between transconjugants arising from each vector library during in vitro conjugations. 18 OTUs were shared between all 3 libraries, with a total of 47 OTUs being shared between at least 2 libraries.