Center: phylo-RPCA ordination comparing ISS surface microbiota, 3DMM (red, this study) and MT1 (blue), to microbiota observed in environmental microbiota studies performed on Earth, with an emphasis on built environments. The relative proximity of the different terrestrial cohorts (sub-studies) to the ISS samples highlights which terrestrial-built environments are more similar to the ISS. Left: boxplots of PC2 loadings across samples in PCA, ordered by median value. Box boundaries denote 25th and 75th percentiles, whereas the whiskers extend up to 1.5 times the IQR. Bottom: linear regression plot with Faiths PD as a function of PC1 sample loadings (Pearson correlation, m denotes the slope). Right: density plots for three selected taxa, generated by applying a log transformation to the moving average ratio of the abundance of each target family (Chitinophagaceae_966727, Paenibacillaceae_367444, and Burkholderiaceae_A_592522) with Staphylococcaceae as the denominator. The abundance of Staphylococcaceae is elevated in more industrial/anthropocentric built environments, resulting in a more negative log ratio. The selection of these families was based on feature loadings along PC2 derived from phylo-RPCA (see STAR Methods).
