Setting new boundaries of 16S rRNA gene identity for prokaryotic taxonomy.

ABSTRACT: The 16S rRNA gene is frequently sequenced to classify prokaryotes and identify new taxa. If sequences from two strains share less than ~99% identity, the strains are usually classified as different species. Classification thresholds for genera and other ranks have also been proposed, but they are based on dated datasets. Here we update these thresholds by determining the sequence identity of the 16S rRNA gene for n=19,556 type strains. This represents 94% of all strains validly published, and it involved making more than 191 million pairwise sequence alignments. In 90% of all cases, sequences from the same species shared a minimum of 97.2-100% identity. The corresponding values were 90.1-99.0% for genus, 80.1-94.1% for family, 72.9-90.0% for order, 72.2-86.3% for class and 69.6-83.6

SUBMITTER: Hackmann TJ 

PROVIDER: S-EPMC12281934 | biostudies-literature | 2025 Apr

REPOSITORIES: biostudies-literature