Where are the pseudogenes in bacterial genomes?

Trends Microbiol. 2001 Nov;9(11):535-40. doi: 10.1016/s0966-842x(01)02198-9.


Most bacterial genomes have very few pseudogenes; notable exceptions include the genomes of the intracellular parasites Rickettsia prowazekii and Mycobacterium leprae. As DNA can be introduced into microbial genomes in many ways, the compact nature of these genomes suggests that the rate of DNA influx is balanced by the rate of DNA deletion. We propose that the influx of dangerous genetic elements such as transposons and bacteriophages selects for the maintenance of relatively high deletion rates in most bacteria; the sheltered lifestyle of intracellular parasites removes this threat, leading to reduced deletion rates and larger pseudogene loads.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacteriophages / genetics
  • Chromosomes, Bacterial
  • DNA Transposable Elements
  • Gene Deletion
  • Gene Transfer, Horizontal
  • Genome, Bacterial
  • Humans
  • Lysogeny
  • Models, Genetic
  • Pseudogenes / genetics*


  • DNA Transposable Elements