FIG 3.

Bacterial species-level genomic diversity (i.e., gene presence/absence and core gene variants) correlates with strain origin. B. cereus and S. aureus are represented in the I and II panels, respectively. (A) Total gene counts for each fraction of the pangenome by strain origin: built environment-Earth (BE-E), -spacecraft (BE-SC), culture-Earth (Cul-E), -spacecraft (Cul-SC), human, and soil samples. BE-SC samples were taken aboard the ISS; Cul-SC samples were clonal isolates sent to space aboard the Shenzhou VIII. (B) PCoA for gene presence/absence among strains. Color/shape corresponds to sample origin. (C) Phylogenetic tree constructed from core gene codon alignment with midpoint rooting. ISS-, human-, and BE-E-sourced strains from the work of Checinska Sielaff et al. (29) and the Wallace and Voorhies data set (Table S1) are shaded in blue, yellow, and gray, respectively.