Laboratory strains of Escherichia coli K-12: not such perfect role models after all.


Escherichia coli K-12 was originally isolated 100 years ago and since then, it has become an invaluable model organism and a cornerstone of molecular biology research. However, despite its apparent pedigree, since its initial isolation, E. coli K-12 has been repeatedly cultured, passaged, and mutagenized, resulting in an organism that carries extensive genetic changes. To understand more about the evolution of this important model organism, we have sequenced the genomes of two ancestral K-12 strains, WG1 and EMG2, considered to be the progenitors of many key laboratory strains. Our analysis confirms that these strains still carry genetic elements such as bacteriophage lambda ({lambda}) and the F plasmid, but also indicates that they have undergone extensive lab-based evolution. Thus, scrutinizing the genomes of ancestral E. coli K-12 strains, leads us to question whether E. coli K-12 is a sufficiently robust model organism for 21st century microbiology.

Publication DOI:
Divisions: College of Health & Life Sciences > School of Biosciences
Additional Information: The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY 4.0 International license.
Uncontrolled Keywords: genomics
Last Modified: 27 Jun 2024 11:58
Date Deposited: 11 Nov 2022 09:03
Full Text Link:
Related URLs: ... .06.29.497745v1 (Publisher URL)
PURE Output Type: ["eprint_fieldname_pure_output_type_workingpaper/preprint" not defined]
Published Date: 2022-06-29
Authors: Browning, Douglas F (ORCID Profile 0000-0003-4672-3514)
Hobman, Jon L
Busby, Stephen JW



Version: Draft Version

License: Creative Commons Attribution

| Preview

Export / Share Citation


Additional statistics for this record