CRISPR provides acquired resistance against viruses in prokaryotes.
Level 5 - mechanism / opinion, no new human data
Level 5 by design analogy (in vitro laboratory and bench microbiology experiment)
PubMed 17379808 · doi:10.1126/science.1138140
What was done
Following viral challenge in bacteria, researchers tested whether phage-derived genomic sequences were incorporated into bacterial CRISPR loci. They also analyzed changes in phage-resistance phenotypes after experimentally adding or removing specific spacer sequences.
What was found
The abstract provides no numerical data or effect sizes. Qualitatively, bacteria integrated new phage-derived spacers after viral exposure, and the addition or deletion of specific spacers modified the phage-resistance phenotype, demonstrating that CRISPR and associated cas genes provide phage resistance determined by sequence similarity.
Why it matters
This study established that prokaryotic CRISPR-Cas systems function as an adaptive, sequence-specific immune mechanism against bacteriophages.
Limits
No quantitative measurements, sample sizes, or variance estimates are reported in the abstract. The specific bacterial species, phage types, and precise experimental conditions are not detailed.
Cited by
- supports CRISPR repeat sequences naturally function as an adaptive immune defense mechanism in bacteria against bacteriophage viruses.
- context CRISPR gene editing technology was discovered through research on how bacteria use enzymes to remember foreign genetic sequences and defend against invaders.