Extended Data Fig. 5. Species and protein cluster sharing between habitats is similar to unigene sharing, but sharing of protein families is more extensive.

(a) The sharing of metagenomic species between habitats mimics unigene sharing. Width of each ribbons represents the number of MGSs shared between the habitats (the largest number shared is between the human and the pig gut, which share 166 MGSs out of 1,908 MGSs in the human gut and 898 in pig gut, respectively). (b) Species-level unigene sharing between habitats by fraction of the number of unigenes from each habitat (cf. Fig. 1b, which uses abundance weighting). (c) Sharing of protein clusters (90% amino acid identity clusters) between habitats, abundance-weighted. (d) Sharing of protein families between habitats, abundance-weighted. When considering coarser clusterings of sequences, gene sharing between habitats increases, yet we still observed higher rates of sharing between similar habitats and significant fractions of habitat-specific families (e.g., in the marine environment, 31.3% of the genes, by abundance, are in marine-specific protein families).