When at the end of the 19th century information began to accumulate about the diversity within the bacterial world, scientists started to include the bacteria in phylogenetic schemes to explain how life on Earth may have developed. Some of the early phylogenetic trees of the prokaryote world were morphology-based; others were based on the then-current ideas on the presumed conditions on our planet at the time that life first developed. Around 1950 many leading microbiologists had become pessimistic with respect to the possibility of ever reconstructing bacterial phylogeny. The concept of the prokaryote-eukaryote dichotomy did little to clarify phylogenetic relationships. The developing technology of nucleic acid sequencing, together with the recognition that sequences of building blocks in informational macromolecules (nucleic acids, proteins) can be used as "molecular clocks" that contain historical information, led to the development of the three-domain model (Archaea - Bacteria - Eucarya) in the late 1970s, primarily based on small subunit ribosomal RNA sequence comparisons. The information currently accumulating from complete genome sequences of an ever increasing number of prokaryotes are now leading to further modifications of our views on microbial phylogeny read more ...

from Molecular Phylogeny of Microorganisms by Aharon Oren and R. Thane Papke (2010)

References

• Molecular Phylogeny of Microorganisms
• Lab-on-a-Chip Technology
• Real-Time PCR: Current Technology and Applications
• Environmental Molecular Microbiology
• Metagenomics

Labels: Bacterial phylogeny, Microbial phylogeny, Phylogenetic relationships, Phylogenetic schemes, Ribosomal RNA sequence comparison