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Methods and reproducibility outputs

This page describes the reproducibility outputs generated by MTD Explorer.

These files are designed to help users audit, reproduce, and report an analysis run.

The main folder is:

methods/
├── mtd_methods_run_parameters.csv
├── used_samplesheet.csv
└── used_fastq_files.tsv

Input provenance files

Two files preserve the exact analysis inputs independently of the original input directory.

Samplesheet copy

methods/used_samplesheet.csv

MTD Explorer copies the exact samplesheet supplied to --input into the output directory at run start. This allows the study design used by that result directory to be recovered even if the original samplesheet is later edited, renamed, or moved.

FASTQ manifest

methods/used_fastq_files.tsv

After FASTQ detection and layout validation, MTD Explorer records one row per sample with these columns:

sample
layout
read1_path
read1_size_bytes
read2_path
read2_size_bytes

The manifest stores resolved absolute FASTQ paths and file sizes in bytes. For single-end samples, the R2 fields are recorded as -. The FASTQ files themselves are not copied into methods/; the manifest records which files were actually resolved and used.

Main reproducibility table

The most important reproducibility file is:

methods/mtd_methods_run_parameters.csv

Example table:

Download example run parameters CSV

This table records the run configuration in a structured format.

The columns are usually:

category
program
parameter
value
description

Each row describes one setting, file path, software version, output pattern, or analysis choice used during the run.

Run metadata

The Run metadata rows record when and how the pipeline was launched.

Typical parameters include:

run_datetime
launch_directory
original_command
MTD_directory
conda_path

The original_command row is especially important because it stores the exact command line used to start the analysis.

This can include input paths, output paths, host taxon settings, custom databases, read extraction options, and analysis parameters.

Input and output paths

The Input and output rows record the main files and folders used by the run.

Typical parameters include:

samplesheet_file
input_directory
output_directory
metadata_file

These rows help users trace the analysis back to the original samplesheet, FASTQ directory, output directory, and optional metadata file.

Study design

The Study design rows record settings that affect biological interpretation.

Typical parameters include:

host_annotation_taxid
host_annotation_species
HAllA_metric

These values help identify the host annotation used for downstream host analysis and the association metric used by HAllA.

Read preparation

The Read preparation rows record preprocessing settings.

Typical parameters include:

no_trim
trim_length
read_layout
prepared_fastq_pattern_se
prepared_fastq_pattern_pe
paired_fastq_record_validation

These rows document whether fastp trimming was used, the minimum read length, the effective SE/PE layout, normalized downstream FASTQ patterns, and paired-record validation behavior.

Host filtering

The Host filtering rows record the Kraken2 settings used to split host and non-host reads.

Typical parameters include:

host_kraken_db
host_kraken_db_mode
host_kraken_db_from_hostid
confidence
minimum_hit_groups
classified_out
unclassified_out

These rows are important because the host filtering step affects which reads are passed to downstream microbiome and functional analyses.

Microbiome classification

The Microbiome classification rows record the Kraken2 database and classification settings used for the non-host read fraction.

Typical parameters include:

microbiome_kraken_db
microbiome_kraken_db_mode
microbiome_kraken_db_default
confidence
minimum_hit_groups
raw_report_pattern
final_report_pattern

These values should be reported when comparing taxonomic profiles across runs.

Contaminant removal

The Contaminant removal rows record whether a contaminant taxid list was available to KrakenTools.

Typical parameters include:

contaminant_list
contaminant_list_status

If contaminant removal is enabled or available, users should check whether the raw and final global composition outputs differ.

Abundance estimation

The Abundance estimation rows record Bracken parameters.

Typical parameters include:

bracken_read_length
bracken_threshold
bracken_distribution_file
bracken_distribution_file_status
taxonomic_levels

These rows are useful for reproducing microbiome abundance estimation.

The read length and distribution file must match the intended Bracken database configuration. The pipeline also records Bracken package metadata and the CLI version banner separately when available. This distinction matters because a packaged Bracken release can expose an older CLI banner; for reproducibility, prefer the recorded package version when identifying the installed Conda build.

Detected microbiome read extraction

The Detected microbiome read extraction rows record whether reads assigned to detected microbiome taxa were extracted.

Typical parameters include:

extract_microbiome_reads
ranking_mode
top_n
min_abundance
include_children

These settings affect downstream per-taxon read extraction and any analyses based on extracted microbiome reads.

Host downstream analysis

The Host downstream analysis rows record host alignment, counting, and ssGSEA-related settings.

Typical programs and tools include Magic-BLAST, HISAT2, featureCounts, and ssGSEA.

Typical parameters include:

host_alignment_mode
read_layout
blast_database
hisat2_database
gtf_file
conda_environment
paired_end_mode
output
gmt_requested
gmt_resolved
gmt_mode
master_gmt
analysis_gmt

The featureCounts rows record the dedicated MTD_featurecounts environment. Paired-end quantification is explicitly recorded as -p plus --countReadPairs, meaning paired alignments are counted as fragments/read pairs. The current runtime validates featureCounts 2.1.1.

The ssGSEA rows distinguish the value requested by the user from the resolved mode/path and record the persistent host master GMT plus the analysis-specific filtered GMT when applicable. This is especially important now that --ssgsea-gmt auto is the default.

Functional profiling

The Functional profiling rows record HUMAnN settings.

Typical parameters include:

input_pattern
threads
renormalization_units

These rows help document how non-host reads were passed into functional profiling and how HUMAnN outputs were normalized.

Association analysis

The Association analysis rows record HAllA settings.

Typical parameters include:

metric
RUN_EXTRA_PEARSON
RUN_FULL_HALLAGRAM
HALLA_DIAGNOSTIC

These values help interpret the integration outputs and clarify whether extra diagnostic or alternative association analyses were enabled.

Key outputs

The Key outputs rows record major result files generated by the run.

Typical parameters include:

raw_global_composition
final_global_composition
species_table
microbiome_input

These paths help users locate the main taxonomic composition table, final species abundance table, and matrix used by HAllA.

Software paths and versions

The Software path and Software version rows record executable paths and best-effort version captures.

Typical programs include:

kraken2
bracken
fastp
pigz
python
Rscript
humann
magicblast
hisat2
featureCounts
samtools

These rows support reproducibility, but they should be interpreted carefully.

A value such as not_found or command not found means that the version capture step did not find that executable in the environment where the capture was attempted.

It does not necessarily mean the whole analysis failed.

Some tools may have been called from another environment, wrapper, module, or step-specific context.

For reproducibility, inspect files in this order:

methods/used_samplesheet.csv
methods/used_fastq_files.tsv
methods/mtd_methods_run_parameters.csv
host_counts.txt
Nonhost_DEG/
Host_DEG/
hmn_genefamily_abundance_files/
ssGSEA/
halla/

Start with the saved samplesheet and FASTQ manifest to confirm the exact inputs, then inspect methods/mtd_methods_run_parameters.csv for parameters, databases, and captured software versions.

Then inspect the output folders relevant to the result you want to reproduce.

What this page can support

The methods outputs can help answer questions such as:

Which command generated this run?
Which databases were used?
Which taxonomic confidence thresholds were used?
Which software versions were captured?
Which files should be cited or checked when reproducing the analysis?

What not to conclude

Do not assume two runs are comparable unless their databases, software versions, read preprocessing settings, taxonomic thresholds, normalization choices, and analysis modes are comparable.

Do not treat a visual output as reproducible without checking the corresponding run-parameter table.

Do not ignore not_found values in the software section; check whether they are expected for that environment or indicate a missing executable.