本文へ移動
cccskills
無料GitHub で公開

bioconductor-dada2

The dada2 package infers exact amplicon sequence variants (ASVs) from high-throughput amplicon sequencing data, replacing the coarser and less accurate OTU clustering approach. The dada2 pipeline takes as input demultiplexed fastq files, an

インストール方法を見る

含まれるファイル(1)

  • SKILL.md5.3 KB

SKILL.md(原文)

インストールする前に、エージェントに与えられる指示の中身を確認できます。

dada2

Dependencies & Environment

Package-intrinsic requirements from the Bioconductor landing page — reproduce in any R environment.

  • Version: 1.40.0 · Bioconductor: 3.23 · R: ≥ 4.6
  • Depends: Rcpp
  • Imports: Biostrings, ggplot2, reshape2, ShortRead, RcppParallel, IRanges, XVector, BiocGenerics
  • System requirements: GNU make
  • Install: BiocManager::install("dada2")

When to Use

  • Resolving exact Amplicon Sequence Variants (ASVs) from high-throughput amplicon sequencing data using the dada algorithm.
  • Filtering and trimming raw paired-end or single-end FASTQ files using filterAndTrim.
  • Modeling and learning sequencing error rates directly from the data using learnErrors.
  • Removing chimeric sequences from merged sequence tables using removeBimeraDenovo.

When NOT to Use

  • For shotgun metagenomic sequencing data (use MetaPhlAn or HUMAnN instead).
  • For clustering sequences based on a fixed 97% identity threshold (use vsearch or UCLUST instead).
  • For downstream ecological statistics and visualization of ASV tables (use phyloseq instead).

Data Requirements

  • Input Format: Demultiplexed FASTQ files (unzipped or gzipped). One file per sample for single-end, or two files per sample for paired-end.
  • Quality Scores: Raw reads must contain quality scores.
  • Primers: Sequences must have non-biological bases (like PCR primers) removed prior to ASV inference.

Key Parameters

  • truncLen: Truncate reads after this many bases. Reads shorter than this are discarded. Crucial for removing low-quality tails.
  • maxEE: After truncation, reads with higher than this number of expected errors are discarded (e.g., maxEE=2).
  • trimLeft: The number of nucleotides to remove from the start of each read (useful for removing primers).
  • maxN: Maximum number of ambiguous nucleotides allowed. DADA2 requires maxN=0.
  • multithread: If TRUE, enables parallel processing to speed up computation.
  • err: The error model generated by learnErrors, passed into the dada function.

Best Practices

  • Inspect the quality profiles of forward and reverse reads using plotQualityProfile before setting truncLen parameters.
  • Learn error rates using learnErrors on at least a subset of your data to ensure accurate sample inference.
  • Maintain a suitable overlap (>20nts) between forward and reverse reads after trimming to ensure mergePairs succeeds.
  • Perform chimera removal using removeBimeraDenovo on the combined sequence table created by makeSequenceTable.

Common Pitfalls

  • Failing to merge paired reads: Truncating reverse reads too aggressively can prevent them from overlapping with forward reads, causing mergePairs to fail. Fix this by ensuring truncLen leaves enough sequence for a >20nt overlap.
  • Leaving primers in the sequences: Non-biological nucleotides distort the error model. Fix this by using trimLeft in filterAndTrim or an external tool to remove primers.
  • Reads dropped due to Ns: DADA2 cannot process sequences with ambiguous bases. Fix this by ensuring maxN=0 is set in filterAndTrim.

Alternatives

  • phyloseq: Used for downstream analysis, visualization, and integration of the ASV tables produced by DADA2.
  • vsearch: An alternative for traditional OTU clustering based on sequence identity thresholds.
  • deblur: An alternative sub-operational taxonomic unit (sOTU) algorithm that uses a static error model.

Citations

  • Callahan BJ, McMurdie PJ, Rosen MJ, Han AW, Johnson AJ, Holmes SP. (2016). "DADA2: High-resolution sample inference from amplicon data." Nature Methods, 13(7), 581-583.
  • Callahan BJ, McMurdie PJ, Holmes SP. (2017). "Exact sequence variants should replace operational taxonomic units in marker-gene data analysis." ISME Journal, 11(12), 2639-2643.

References

<!-- biomate-cta -->

Run this on BioMate

This skill is the knowledge layer — when, why, and how to use dada2. To run this analysis on your own data with managed compute, automated QC, and reproducible outputs, use BioMate — free to start.

▶ Open dada2 on BioMate →

レビュー

まだレビューはありません。使ってみた感想をお寄せください。

同じリポジトリのスキル

概要と使いどころ

The package contains functions for exploratory oligonucleotide array analysis. The dependence on tkWidgets only concerns few convenience functions. 'affy' is fully functional without it.

日本語の概要は準備中です。原文の説明を表示しています。

bioMate-AI/biomate-bioconductor-kb8042026年6月21日 更新

This tool uses the label-tree function from HyPhy to annotate a phylogenetic tree. It allows users to select a subset of leaves using either a regular expression or a list of sequence names, and then apply a specified label to these selecte

日本語の概要は準備中です。原文の説明を表示しています。

bioMate-AI/biomate-bioconductor-kb8042026年6月21日 更新

This package provides a client for the Bioconductor AnnotationHub web resource. The AnnotationHub web resource provides a central location where genomic files (e.g., VCF, bed, wig) and other resources from standard locations (e.g., UCSC, En

日本語の概要は準備中です。原文の説明を表示しています。

bioMate-AI/biomate-bioconductor-kb8042026年6月21日 更新

apeglm provides Bayesian shrinkage estimators for effect sizes for a variety of GLM models, using approximation of the posterior for individual coefficients.

日本語の概要は準備中です。原文の説明を表示しています。

bioMate-AI/biomate-bioconductor-kb8042026年6月21日 更新

ASURAT is a software for single-cell data analysis. Using ASURAT, one can simultaneously perform unsupervised clustering and biological interpretation in terms of cell type, disease, biological process, and signaling pathway activity. Inputting a single-cell RNA-seq data and knowledge-based databases, such as Cell Ontology, Gene Ontology, KEGG, etc., ASURAT transforms gene expression tables into original multivariate tables, termed sign-by-sample matrices (SSMs).

日本語の概要は準備中です。原文の説明を表示しています。

bioMate-AI/biomate-bioconductor-kb8042026年6月21日 更新

AUCell allows to identify cells with active gene sets (e.g. signatures, gene modules...) in single-cell RNA-seq data. AUCell uses the "Area Under the Curve" (AUC) to calculate whether a critical subset of the input gene set is enriched with

日本語の概要は準備中です。原文の説明を表示しています。

bioMate-AI/biomate-bioconductor-kb8042026年6月21日 更新

bioMate-AI のスキルをすべて見る

このスキルの問題を報告する