Journal of Molecular Evolution

, Volume 62, Issue 6, pp 807–808 | Cite as

The Histidine Operon Is Ancient

  • Morgan N. Price
  • Eric J. Alm
  • Adam P. Arkin
Letter to the Editor

Fani et al. (2005) studied the organization of the histidine synthesis genes across the Proteobacteria. They reported that the unified operon hisGDC(NB)HAF(IE) found in Escherichia coli, where hisNB and hisIE are gene fusions, is broken up in many Proteobacteria. They considered that the common ancestor of the Proteobacteria may have had this unified organization and it was then broken up in several lineages, or that the unified operon may have evolved by joining several pieces. They favored the joining model, with the unified operon forming in the ancestor of the ß/γ-Proteobacteria, because they thought it unlikely that the operon would independently break up multiple times. However, they restricted their analysis to the Proteobacteria and considered other genomes as being outside the scope of their study.

As can be seen with the MicrobesOnline comparative genome browser (e.g.,, bacteria across many phyla have a compact histidine operon,...


Mycobacterium Tuberculosis Horizontal Transfer Unify Organization Operon Structure Sulfolobus Solfataricus 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This work was supported by a grant from the DOE Genomics:GTL program (DE-AC03-76SF00098).


  1. Bond JP, Francklyn CF (2000) Proteobacterial histidine-biosynthetic pathways are paraphyletic. J Mol Evol 50:339–347PubMedGoogle Scholar
  2. Fani R, Brilli M, Lio P (2005) The origin and evolution of operons: the piecewise building of the proteobacterial histidine operon. J Mol Evol 60:370–390CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  • Morgan N. Price
    • 1
    • 2
  • Eric J. Alm
    • 2
    • 5
    • 6
  • Adam P. Arkin
    • 1
    • 2
    • 3
    • 4
  1. 1.Lawrence Berkeley National LabBerkeleyUSA
  2. 2.Virtual Institute for Microbial Stress and SurvivalBerkeleyUSA
  3. 3.Department of BioengineeringUniversity of California at BerkeleyBerkeleyUSA
  4. 4.Howard Hughes Medical Institute of BerkeleyBerkeleyUSA
  5. 5.Departments of Biological Engineering and Civil and Environmental EngineeringMassachusetts Institute of TechonologyCambridgeUSA
  6. 6.Massachusetts Institute of TechonologyCambridgeUSA

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