Back تجربة تطور الإشريكية القولونية طويلة الأمد Arabic Lenski təcrübəsi Azerbaijani E. coli langtids-evolutionseksperimentet Danish Experimento a largo plazo de la evolución de E. Coli Spanish ניסוי האבולוציה של אי קולי HE Eksperimen evolusi jangka panjang E. coli ID 대장균의 장기간 진화 실험 Korean Experimento de evolução de longo prazo de E. coli Portuguese Долговременный эксперимент по эволюции E. coli Russian Дугорочни експеримент еволуције ешерихије коли Serbian

E. coli long-term evolution experiment

The 12 E. coli LTEE populations on June 25, 2008.[1]

The E. coli long-term evolution experiment (LTEE) is an ongoing study in experimental evolution begun by Richard Lenski at the University of California, Irvine, carried on by Lenski and colleagues at Michigan State University,[2] and currently overseen by Jeffrey Barrick at the University of Texas at Austin.[3] It has been tracking genetic changes in 12 initially identical populations of asexual Escherichia coli bacteria since 24 February 1988.[4] Lenski performed the 10,000th transfer of the experiment on March 13, 2017.[5] The populations reached over 73,000 generations in early 2020, shortly before being frozen because of the COVID-19 pandemic.[6] In September 2020, the LTEE experiment was resumed using the frozen stocks.[7] When the populations reached 75,000 generations, the LTEE was transferred from the Lenski lab to the Barrick lab.[3] In August 2024, the LTEE populations passed 80,000 generations in the Barrick lab.[8]

Over the course of the experiment, Lenski and his colleagues have reported a wide array of phenotypic and genotypic changes in the evolving populations. These have included changes that have occurred in all 12 populations and others that have only appeared in one or a few populations. For example, all 12 populations showed a similar pattern of rapid improvement in fitness that decelerated over time, faster growth rates, and increased cell size. Half of the populations have evolved defects in DNA repair that have caused mutator phenotypes marked by elevated mutation rates. The most notable adaptation reported so far is the evolution of aerobic growth on citrate, which is unusual in E. coli, in one population at some point between generations 31,000 and 31,500.[9][10] However, E. coli usually does grow on citrate in anaerobic conditions and has an active citric acid cycle which can metabolize citrate even under aerobic conditions.[11] The aerobic event is mainly an issue of citrate being able to enter the cell.[12][11]

On May 4, 2020, Lenski announced a 5-year renewal of the grant through the National Science Foundation's Long-Term Research in Environmental Biology (LTREB) Program that supports the LTEE.[13] He also announced that Dr. Jeffrey Barrick, an associate professor of Molecular Biosciences at The University of Texas at Austin, would take over supervision of the experiment within the 5-year funding period.[14] The experiment's time at Michigan State University ended in May 2022, when the populations reached 75,000 generations but the experiment was revived and restarted in Barrick's lab on June 21, 2022.[3]

  1. ^ Pennisi, Elizabeth (14 November 2013). "The Man Who Bottled Evolution". Science. 342 (6160): 790–793. Bibcode:2013Sci...342..790P. doi:10.1126/science.342.6160.790. PMID 24233702.
  2. ^ Cite error: The named reference photos was invoked but never defined (see the help page).
  3. ^ a b c Barrick, Jeffrey (2022-06-21). "LTEE Kickoff at UT Austin". The Long-Term Evolution Experiment. Retrieved 2022-06-22.
  4. ^ Lenski, Richard E. (2000). "Source of founding strain". Richard E. Lenski Homepage. Michigan State University. Archived from the original on 2018-05-31. Retrieved 2008-06-18.
  5. ^ "Some Wrinkles in Time". Telliamed Revisited. 2017-03-13. Retrieved 2017-03-13.
  6. ^ Lenski, Richard E. (2020-03-09). "We Interrupt this Nasty Virus with Some Good News about Bacteria". Telliamed Revisited. Retrieved 2021-05-27.
  7. ^ "They're back!". Telliamed Revisited. 2020-09-22. Retrieved 2021-06-17.
  8. ^ "80,000 Generations: New Olympic Record – the Long-Term Evolution Experiment".
  9. ^ Cite error: The named reference pmid18524956 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Blount2012 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Evo-Ed was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference pmid6358185 was invoked but never defined (see the help page).
  13. ^ "Long Term Research in Environmental Biology (LTREB)". new.nsf.gov. National Science Foundation. 9 December 2020. Retrieved 10 June 2024.
  14. ^ "Five More Years". Telliamed Revisited. 2020-05-04. Retrieved 2020-05-09.

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