Fig. 3

Relating viral contigs from Cr-contaminated soils to known viral sequence space. Viral contigs recovered from Cr-contaminated soils were clustered with all RefSeq (v 75) viral genomes or genome fragments with genetic connectivity to these data. Each node colors indicate sample and reference viral sequences’ habitat of origin. The edges (lines) between the nodes represent statistically weighted pairwise similarity scores of ≥ 1. The results show that viromes at different sites along a Cr-contaminated soil gradient have distinct specificity. And only a few of recovered viral contigs were associated with viruses recorded in NCBI databases (RefSeq, v 75) from soil, water, human, and sediment habitats