Introduction - Bacterial/ Microbial Phylogeny (Evolution)

Chronology of major events in the history of life
Chronology of major events in the history of life

Prokaryotic organisms were the sole inhabitants of this planet for the first 2-2.5 billion years. To understand such fundamental questions as the nature and origin of the first cell, origin of different types of metabolism, information transfer processes, photosynthesis, origin of the eukaryotic cells, evolution of disease-causing as well as beneficial microbes, a sound understanding of the bacterial (prokaryotic) evolution is essential. The analyses of genome sequence data using new approaches are providing valuable insights in understanding some of these most ancient and important aspects of the evolutionary history of life. This website, presents information using novel comparative genomic approaches, that are helpful in understanding the following critical issues in bacterial/prokaryotic phylogeny:


  1. Molecular means to clearly define and circumscribe the major groups/subgroups within Bacteria and Archaea in unambiguous terms.
  2. Means to logically delineate the branching order and hierarchical relationships among the major groups/taxa within Bacteria.
  3. Criteria for the higher taxonomic ranks within Bacteria.
  4. Evolutionary relationships among Photosynthetic bacteria.
  5. Consideration of the relationships between Bacteria and Archaea.
  6. Assessment of the extant of lateral gene transfer and its impact on Bacterial phylogeny.
  7. Implications of the Prokaryotic evolution on the Origin of the Eukaryotic cell.

Citation for this webpage (Last update April 2007):
Bacterial (Prokaryotic) Phylogeny Webpage (March 2006).
This website is maintained by members of the Gupta lab. Information presented here is solely for educational/scientific purposes. Images, text and other items from here can be used for educational purposes provided appropriate credit to this site and to the primary publication(if applicable) is given. For questions/comments, please contact (