Toward DNA-based taxonomy of prokaryotes and microeukaryotes

The current nomenclatural rules regulating the naming of microorganisms are too conservative from the perspective of recent developments in molecular genetics tools and organism discovery. The taxonomy of microorganisms would greatly benefit from a conceptual shift toward DNA-based approaches. Current informal practices of DNA-based taxonomy include the use of DNA sequences for species description and type material. Here, we analyze the pros and cons of DNA-based taxonomic approaches and propose guidelines and examples for their appropriate use in descriptions of species and higher-ranking taxa. To facilitate taxon description and communication, we call for a broader use of DNA samples, genome and genetic marker sequences in typifying and diagnosing species and higher-ranking taxa if physical voucher strains or specimens are unavailable.