The availability of sequence data from an ever-wider sampling of organisms has revolutionized our view of life diversity by showing that microorganisms dominate all ecosystems. However, this has also had an impact on the field of taxonomy. At low taxonomic level, microbial systematics relies on operational and arbitrary definitions based on various criteria (e.g. percentage of genomic DNA–DNA hybridization, similarity of 16S ribosomal RNA genes, molecular typing and multilocus sequence typing) [1]. However, when it comes to higher-level taxonomy, no general rules apply.
展开▼
