Microbiome Analysis Techniques and Sample Processing

Advances in microbiome research hinge upon robust methods for DNA extraction, library preparation and data interpretation. Two principal sequencing strategies dominate the field: marker-gene surveys, most commonly targeting the 16S rRNA gene, and untargeted shotgun metagenomics. Marker-gene sequencing remains cost-effective for large cohort studies, but can introduce amplification bias and limits taxonomic resolution. Shotgun approaches capture broader functional potential and strain-level variation, yet demand greater sequencing depth and more complex bioinformatic workflows. Core to both approaches is the choice of sample collection and preservation protocol, which must minimise compositional shifts and DNA degradation. Standardised workflows for mechanical and chemical lysis, bead-beating and enzyme treatments are essential to ensure representative recovery of hard-to-lyse taxa. Equally critical is the implementation of contamination-control measures, including the use of negative and positive controls, mock communities and in silico decontamination pipelines. Downstream analysis frameworks have evolved from operational taxonomic unit (OTU) clustering to amplicon sequence variant (ASV) inference, enabling higher specificity and cross-study comparability. Integration of reference phylogenies unifies disparate datasets, while dual-index and heterogeneity spacer designs mitigate sequencing artefacts on high-throughput platforms. Collectively, these methodological refinements underpin applications ranging from human health diagnostics to environmental monitoring and agricultural biotechnology, emphasising the global significance of reproducible microbiome analysis.

Research from Nature Portfolio

Recent studies have introduced unified reference frameworks that bridge marker-gene and shotgun datasets. A novel integrated phylogenetic tree allows insertion of both 16S rRNA sequences and whole genomes, demonstrating concordant community structure and effect sizes across methodologies. Foundational work on full-length 16S rRNA gene sequencing has shown that complete gene coverage markedly improves species and strain discrimination compared to short-read variable-region surveys, highlighting the necessity of accounting for intragenomic copy variation. In the realm of sample processing, comparative evaluation of common storage strategies revealed that simple refrigeration preserves faecal microbiota composition as effectively as immediate freezing to –80 °C over days, whereas several chemical stabilisers introduce systematic shifts that must be corrected in downstream analyses. These insights have refined best practices for field and clinical studies where cold-chain logistics may be limited.

Microbiome Analysis Techniques and Sample Processing publication trend

The graph below shows the total number of articles in microbiome analysis techniques and sample processing across all publications each year (not limited to Nature Index journals).

Technical terms

16S rRNA gene sequencing: Targeted amplification and sequencing of the ribosomal RNA gene used for taxonomic profiling of bacteria and archaea.

Shotgun metagenomics: Untargeted sequencing of total community DNA to assess taxonomic composition and functional potential.

Amplicon sequence variant (ASV): A highly resolved, denoised sequence inferred from raw reads that represents a unique biological sequence.

Operational taxonomic unit (OTU): A cluster of similar sequences, often defined by a set similarity threshold, used to approximate microbial taxa.

Reference phylogeny: A curated evolutionary tree into which sample sequences are placed to enable consistent taxonomic and functional comparison.

References

1. Greengenes2 unifies microbial data in a single reference tree. Nature Biotechnology (2023).
2. Using strain-resolved analysis to identify contamination in metagenomics data. Microbiome (2023).
3. Simple statistical identification and removal of contaminant sequences in marker-gene and metagenomics data. Microbiome (2018).
4. Evaluation of 16S rRNA gene sequencing for species and strain-level microbiome analysis. Nature Communications (2019).
5. An improved dual-indexing approach for multiplexed 16S rRNA gene sequencing on the Illumina MiSeq platform. Microbiome (2014).
6. The truth about metagenomics: quantifying and counteracting bias in 16S rRNA studies. BMC Microbiology (2015).
7. Preservation Methods Differ in Fecal Microbiome Stability, Affecting Suitability for Field Studies. mSystems (2016).
8. Evaluation of Methods for the Extraction and Purification of DNA from the Human Microbiome. PLOS ONE (2012).
9. Optimizing methods and dodging pitfalls in microbiome research. Microbiome (2017).