Genomic Taxonomy and Phylogenetic Analysis of Microbial Species

Genomic taxonomy and phylogenetic analysis leverage whole‐genome sequence data to redefine microbial species boundaries and evolutionary relationships. By moving beyond single‐gene markers such as 16S rRNA, modern approaches calculate genome‐wide similarity metrics—most notably average nucleotide identity (ANI) and in-silico genome-to-genome hybridisation (GGDH)—to assess relatedness at strain, species and genus levels. High-throughput pipelines integrate curated databases, type‐strain genome repositories and automated phylogenomic inference to produce robust, reproducible classification frameworks. These methods elucidate hidden microdiversity within natural populations, reveal cryptic lineages among uncultured taxa and enable consistent taxonomic revisions across diverse phyla. Applications range from tracking pathogen emergence and antimicrobial resistance to bioprospecting environmental microbiomes and optimising industrial fermentations, underlining the global importance of an accurate, genome-based microbial systematics.

Research from Nature Portfolio

Recent studies have exploited deep sampling and high‐resolution genomics to quantify intra‐species diversity. In one investigation of Salinibacter ruber from solar salterns, researchers identified a natural ANI gap delineating “genomovars” and established ultra‐high thresholds to define strains, revealing thousands of rare variants in a single pond and highlighting cultivation bias in standard isolation methods. Another line of work introduced a fully automated platform for genome-based taxonomy, enabling users to upload draft or complete genomes, infer large‐scale phylogenies anchored on reference type strains, and receive objective species and subspecies boundary estimates. This platform also integrates nomenclatural information and synonymy, streamlining the formal description of new taxa and fostering consistent reclassification of problematic lineages.

Genomic Taxonomy and Phylogenetic Analysis of Microbial Species publication trend

The graph below shows the total number of articles in genomic taxonomy and phylogenetic analysis of microbial species across all publications each year (not limited to Nature Index journals).

Technical terms

Average Nucleotide Identity (ANI): measure of nucleotide-level genomic similarity between two microbial genomes, used to define species boundaries.

Genomovar: intra-species genomic variant defined by discrete gaps in ANI values, reflecting natural subdivisions below species rank.

Phylogenomic inference: reconstruction of evolutionary relationships using genome-scale sequence data rather than single-gene markers.

Type strain: reference microbial isolate to which a species name is formally attached and against which other strains are compared.

In-silico genome-to-genome hybridisation (GGDH): computational method estimating overall genomic relatedness as a digital analogue to laboratory DNA–DNA hybridisation.

References

1. Towards estimating the number of strains that make up a natural bacterial population. Nature Communications (2024).
2. Introducing EzBioCloud: a taxonomically united database of 16S rRNA gene sequences and whole-genome assemblies. International Journal of Systematic and Evolutionary Microbiology (2017).
3. TYGS is an automated high-throughput platform for state-of-the-art genome-based taxonomy. Nature Communications (2019).
4. Analysis of 1,000+ Type-Strain Genomes Substantially Improves Taxonomic Classification of Alphaproteobacteria. Frontiers in Microbiology (2020).