(a) Polymorphism levels, estimated using the density of intermediate alleles (SNPs with a frequency in the range 20%-80%), are shown for 35 MAGs of participant B that had at least 10x coverage. (b) Host classification for the 44 MAGs of participant B. (c) The distribution among element classes, stratified according to element type (shared and non-shared). Data are normalized so that each type sums to 100%. (d) The distribution among element classes, stratified according to host class. Data are normalized so that each host class sums to 100%. Standard deviations are depicted using error bars.