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Updated: Jul 2, 2025
10:39
Methodology for the Study of Horizontal Gene Transfer in Staphylococcus aureus
Published on: March 10, 2017
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Defense systems and horizontal gene transfer in bacteria
Roman Kogay1, Yuri I Wolf1, Eugene V Koonin1
1National Center for Biotechnology Information, National Library of Medicine. National Institutes of Health, Bethesda, MD 20894, USA.
Biorxiv : the Preprint Server for Biology
|February 27, 2024
Summary
Bacterial defense systems, particularly CRISPR-Cas, can limit horizontal gene transfer (HGT) by restricting mobile genetic elements like phages. This finding suggests defense mechanisms play a key role in bacterial evolution and adaptation.
Area of Science:
- Evolutionary biology
- Microbiology
- Genetics
Background:
- Horizontal gene transfer (HGT) is crucial for prokaryotic evolution, driving diversification and adaptation.
- Mobile genetic elements (MGEs) like plasmids and phages typically facilitate HGT but can incur fitness costs.
- Bacterial defense systems are known to combat MGEs, prompting investigation into their role in restricting HGT.
Approach:
- Examined the correlation between HGT rates and the presence of 73 defense systems across 12 bacterial species.
- Analyzed pangenome size and the abundance of phage-related genes in hosts with and without specific defense systems.
Key Points:
- Only 6 defense systems, including 3 CRISPR-Cas subtypes, were significantly associated with reduced gene gain rates.
- Bacteria with these defense systems exhibited smaller pangenomes and fewer phage genes.
- Defense systems appear to inhibit HGT by limiting prophage integration.
Conclusions:
- Bacterial defense systems, especially CRISPR-Cas, can actively restrict horizontal gene transfer.
- This restriction may be species-specific, influenced by ecological and genetic factors.
- Defense mechanisms contribute to shaping bacterial genome evolution by controlling MGE influx.
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