Figure 1.

Taxonomic assignment of metagenomic reads (a) Percentage of the sequence reads classified by the taxonomic grouping based on BLASTX similarity search with NCBI nr database (E-value < 10⁻³). Sequences with no hits with E-value > 10⁻³ were regarded as unidentified reads (“no annotation” category in the table and red in the pie graphs). “LUCA” (last universal common ancestor) (green) denotes reads that could not unambiguously be assigned to a domain of life. (b) Taxonomic assignment of metagenomic reads based on BLASTX similarity search with viral RefSeq database (E-value < 10⁻³). (c) Comparison of the annotation results of NCBI nr and viral RefSeq.