microbial_profiles

Reference-based taxonomic and functional profiling of microbial communities. Use this when you want to know “which species are here and what can they do” without committing to a de novo assembly.

What it does

MetaPhlAn 4 maps reads against species-specific marker genes and produces a relative-abundance profile per sample. The pipeline always runs with --profile_vsc, so a parallel viral-marker profile is emitted alongside the bacterial profile.
MetaPhlAn merge combines per-sample profiles into a single abundance table across all samples.
HUMAnN 3 uses the MetaPhlAn output to pick species-specific pangenomes from ChocoPhlAn, aligns reads against them, and falls back to UniRef90 for unmapped reads. Output is per-sample gene-family and pathway-abundance tables (normalized to CPM via --units cpm).
HUMAnN merge combines per-sample gene-family and pathway tables.

Inputs

--input — samplesheet of QC’d reads.
--metaphlan_db — MetaPhlAn 4 marker database (from download_databases).
--humann3_nucleo — HUMAnN ChocoPhlAn nucleotide database.
--humann3_uniref90 — HUMAnN UniRef90 protein database.

Parameters

Parameter	Type	Default	Controls
`--input`	path	(required)	Samplesheet of clean reads.
`--outdir`	path	(required)	Result directory.
`--metaphlan_db`	path	—	MetaPhlAn 4 database.
`--humann3_nucleo`	path	—	ChocoPhlAn DB.
`--humann3_uniref90`	path	—	UniRef90 DB.

Output

Path (relative to `--outdir`)	Content
`metaphlan/individual_profiles/<sample>_microbial_profile.txt`	Per-sample MetaPhlAn species table (relative abundance).
`metaphlan/individual_profiles/<sample>_viral_profile.txt`	Per-sample viral marker profile (always produced — `--profile_vsc` is on by default).
`metaphlan/microbial.txt`	Species-by-sample abundance matrix across the whole study.
`humann/<sample>_genefamilies.tsv`	Per-sample gene-family abundance (UniRef90 IDs, CPM-normalized).
`humann/<sample>_pathabundance.tsv`	Per-sample MetaCyc pathway abundance (CPM-normalized).
`humann/gene_families.tsv`	Gene-family-by-sample abundance matrix.
`humann/path_abundances.tsv`	Pathway-by-sample abundance matrix.
`pipeline_info/microbial_profiles_multiqc_report.html`	Consolidated MultiQC.

The two humann/ merged tables and the metaphlan/microbial.txt table are the typical inputs to downstream statistical analysis.

Example

nextflow run schirmer-lab/metagear -profile docker \
  --workflow microbial_profiles \
  --input clean.csv \
  --outdir profiles/ \
  --metaphlan_db /data/metagear/metaphlan \
  --humann3_nucleo /data/metagear/humann/chocophlan \
  --humann3_uniref90 /data/metagear/humann/uniref90_diamond

Notes

MetaPhlAn 4 is reference-based. Species that are not in the marker database will not be reported, even if they are abundant in your sample. For novel-organism discovery, complement with gene_analysis.
HUMAnN memory. HUMAnN scales with diversity; 16 GB+ per sample is typical and large/diverse samples (e.g. soil) may need much more.
CPM units. humann_renorm_table is run with --units cpm. If you need RPK or relative abundance, post-process the merged tables with the HUMAnN utilities.
Viral profiles are produced by default via MetaPhlAn’s VSC mode. The per-sample *_viral_profile.txt files contain viral-marker hits; these are useful as a quick check but are reference-limited (only viruses in MetaPhlAn’s marker set).