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Evolutionary Genomics of Defense Systems in Archaea and Bacteria
Eugene V Koonin1, Kira S Makarova1, Yuri I Wolf1
1National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894;
Annual Review of Microbiology
|June 29, 2017
Summary
Prokaryotes possess numerous antiparasite defense systems, including innate and adaptive immunity, crucial for survival. These systems evolve through gene gain/loss and co-opt mobile genetic elements, often linking immunity with programmed cell death.
Area of Science:
- Microbial evolution
- Prokaryotic genetics
- Molecular biology
Background:
- Bacteria and archaea engage in constant conflict with genetic parasites.
- A significant portion of prokaryotic genes are dedicated to antiparasite defense mechanisms.
Purpose of the Study:
- To explore the diverse strategies employed by prokaryotic antiparasite defense systems.
- To highlight recent discoveries in microbial immunity, including novel innate and adaptive systems.
- To elucidate general principles governing the evolution and function of these defense systems.
Main Methods:
- Comparative genomic analysis of microbial genomes and metagenomes.
- Experimental validation of newly discovered defense systems.
- Investigating evolutionary trajectories of defense genes and mobile genetic elements.
Main Results:
- Discovery of previously unknown defense systems, such as Argonaute-centered innate immunity and new CRISPR-Cas variants.
- Identification of key evolutionary principles: extensive gene turnover, formation of defense islands, and recruitment of mobile elements.
- Evidence for selfish or addictive behaviors within defense systems and their coupling with programmed cell death.
Conclusions:
- Prokaryotic defense systems are diverse and dynamic, shaped by co-evolution with parasites.
- Understanding these systems reveals fundamental insights into microbial survival and genome evolution.
- The interplay between immunity, mobile elements, and cell fate is a critical aspect of prokaryotic biology.
Keywords:
CRISPR-Casadaptive immunityantivirus defensedormancyinnate immunitymobile genetic elementsprogrammed cell deathrestriction-modificationtoxins-antitoxinsMore Related Videos
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