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Two faces of the prokaryote concept.
1Department of Biology,York University, Toronto, Ontario, Canada. jsapp@yorku.ca
Summary
The prokaryote concept, established in 1962, initially unified cell structure and evolutionary history. Modern microbial phylogenetics reveals prokaryotes are polyphyletic, challenging the term's continued use.
Area of Science:
- Microbiology
- Evolutionary Biology
- History of Science
Background:
- The 1962 paper "The concept of a bacterium" by Stanier and van Niel defined the prokaryote-eukaryote dichotomy.
- This dichotomy initially distinguished between organizational (cell structure) and phylogenetic (natural classification) concepts.
Purpose of the Study:
- To examine the historical context and evolution of the prokaryote concept.
- To analyze how organizational and phylogenetic definitions became intertwined.
- To discuss the impact of molecular evolutionary biology on understanding bacterial phylogeny.
Main Methods:
- Historical analysis of biological concepts.
- Review of key publications in microbiology and evolutionary biology.
- Examination of the shift in bacterial phylogenetics due to molecular data.
Main Results:
- The prokaryote concept initially implied a monophyletic group preceding eukaryotes.
- This view persisted for 15 years until molecular methods (16S rRNA) emerged.
- Current consensus is that prokaryotes represent a polyphyletic group.
Conclusions:
- The historical intertwining of organizational and phylogenetic definitions shaped the understanding of prokaryotes.
- Modern microbial phylogenetics challenges the monophyletic view of prokaryotes.
- Debate continues on whether to retain the term "prokaryote" in an organizational context.
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