Evidence map›Paper›PMID 33122438›Full record

ReviewProceedings of the National Academy of Sciences of the United States of America2020

It is unclear how important CRISPR-Cas systems are for protecting natural populations of bacteria against infections by mobile genetic elements.

Edze R Westra, Bruce R Levin

Abstract readReview
In one paragraph

Review in Proceedings of the National Academy of Sciences of the United States of America, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 36 papers.

0numbers the graph read from it
0cells of the map it votes in
36citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

36 citing papers in PubMed.

  1. Article
  2. Molecular kinetics dictate population dynamics in CRISPR-based plasmid defense.Proceedings of the National Academy of Sciences of the United States of America · 2026
    Article
  3. Article
  4. Article
  5. Phage susceptibility to a minimal, modular synthetic CRISPR-Cas system inPhilosophical transactions of the Royal Society of London. Series B, Biological sciences · 2025
    Article
  6. Article
  7. Article
  8. Article
  9. Article
  10. Article
  11. Article
  12. Review
  13. Article
  14. Article
  15. Article
  16. Article
  17. Article
  18. Article
  19. Article
  20. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

2 authors.

Edze R WestraEnvironment and Sustainability Institute, Biosciences, University of Exeter, Penryn, TR10 9FE Cornwall, United Kingdom; westra.edze@gmail.com blevin@emory.edu.ORCID 0000-0003-4396-0354
Bruce R LevinDepartment of Biology, Emory University, Atlanta, GA 30307 westra.edze@gmail.com blevin@emory.edu.ORCID 0000-0003-3600-2780

Funding

Theoretical and experimental strudy of the population and evolutionary dynamics oR01GM091875 · NIGMS · EMORY UNIVERSITY · PI LEVIN, BRUCE RICHARD · 2009 to 2017
$2.5M
Theoretical and Experimental Studies of the Population and Evolutionary Dynamics of Bacteria and Bacteriophage.R35GM136407 · NIGMS · EMORY UNIVERSITY · PI LEVIN, BRUCE RICHARD · 2020 to 2024
$2.0M
Biotechnology and Biological Sciences Research Council BB/N017412/1NIGMS NIH HHS R01 GM091875NIGMS NIH HHS R35 GM136407
6 · The paper itself

Abstract

Articles on CRISPR commonly open with some variant of the phrase "these short palindromic repeats and their associated endonucleases (Cas) are an adaptive immune system that exists to protect bacteria and archaea from viruses and infections with other mobile genetic elements." There is an abundance of genomic data consistent with the hypothesis that CRISPR plays this role in natural populations of bacteria and archaea, and experimental demonstrations with a few species of bacteria and their phage and plasmids show that CRISPR-Cas systems can play this role in vitro. Not at all clear are the ubiquity, magnitude, and nature of the contribution of CRISPR-Cas systems to the ecology and evolution of natural populations of microbes and the strength of selection mediated by different types of phage and plasmids to the evolution and maintenance of CRISPR-Cas systems. In this perspective, with the aid of heuristic mathematical-computer simulation models, we explore the a priori conditions under which exposure to lytic and temperate phage and conjugative plasmids will select for and maintain CRISPR-Cas systems in populations of bacteria and archaea. We review the existing literature addressing these ecological and evolutionary questions and highlight the experimental and other evidence needed to fully understand the conditions responsible for the evolution and maintenance of CRISPR-Cas systems and the contribution of these systems to the ecology and evolution of bacteria, archaea, and the mobile genetic elements that infect them.

Indexed as

ArchaeaBacteriaBacteriophagesComputer SimulationCRISPR-Cas SystemsEvolution, MolecularGene Transfer, HorizontalInterspersed Repetitive SequencesModels, TheoreticalPlasmidsVirusesbacteriaCRISPR-Casevolutionphage

Identifiers

PMID33122438
PMCPMC7668106

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.