OSU microbiologists propose updates to the Linnaean System

Wednesday, November 30, 2022

Media Contact: Harrison Hill | Senior Research Communications Specialist | 405-744-5827 | harrison.c.hill@okstate.edu

When Dr. Wouter D. Hoff looks at how the world is classified, he sees an outdated system.

For almost 300 years, the Linnaean Natural System has been the predominant method for naming and classifying organisms. As such, this system plays a central and critical role in the biological sciences. However, a system with such a history does not come without its own imperfections.

Microbiologists at Oklahoma State University are hoping to start a conversation that would make lasting improvements to the Linnaean System through a recent scientific publication.

“This updated Linnaean system is intended to accurately reflect the “tree of life” containing all biological organisms,” said Hoff, professor of microbiology and molecular genetics at OSU.

The current system offers an indispensable approach to organizing biological information and the diversity of life based on evolutionary processes, Hoff said. It also provides a framework for future research. But, rapid progress in discovering novel organisms, particularly microorganisms, has resulted in rising challenges to the system.

Presently, the system has two parts: placing evolutionarily related organisms into their respective taxonomic groups and recognizing seven different taxonomic ranks.

These seven ranks consist of kingdom, phylum, class, order, family, genus and species. Above the kingdom classification, Hoff and his coauthors are proposing adding empire, domain and world. These would accommodate newly discovered diversity in the biological world in the Linnaean system.

“The need for these new named ranks is based on an analysis of a large body of published scientific work that has been yielding increasingly solid insights into biological diversity and evolution,” Hoff said. “These developments are largely driven by research on microscopic organisms such as bacteria and viruses over the past five decades, in which the DNA sequencing revolution played a key role.”

Hoff, along with his collaborators from Amsterdam, are proposing three main changes. First, the animal and fungi kingdoms will be placed into group opisthokonta under the rank of empire, as the two kingdoms are closely related. Second, cellular organisms would be recognized as either eukaryotes, bacteria or archaea under the rank domain. Third, viruses will be placed in their own world since they do not share an ancestral relationship with cellular organisms.

"The current challenge is to formally include these novel findings into the Linnaean Natural System, which has not been able to keep up with the remarkable pace of research on microbial organisms,” Hoff said. “Our manuscript is intended to help address this challenge, and to stimulate conversations on how to achieve that.”

While attempts have been made to make similar changes in the past, Hoff is hopeful that this new proposition will stand out from the rest because of its comprehensive nature, bringing with it a more efficient and accurate classification process in the future.

“Here, we propose a coherent plan for incorporating this avalanche of research into an updated Linnaean system, allowing the great progress on understanding microbial diversity to be properly accommodated” Hoff said.

Story By: Sam Milek | smilek@okstate.edu