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Recruitment of Mobile Genetic Elements for Diverse Cellular Functions in Prokaryotes

Sean Benler1, Eugene V Koonin1

  • 1National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, United States.

Frontiers in Molecular Biosciences
|April 11, 2022
PubMed

Insights

Mobile genetic elements (MGE) in prokaryotes can lose autonomy but gain new host-beneficial functions through exaptation. This evolutionary process primarily enhances microbial defense systems against viruses and other MGE.

Area of Science:

  • Microbial evolution
  • Genomics
  • Molecular biology

Background:

  • Prokaryotic genomes contain numerous mobile genetic elements (MGE) with varying replication autonomy.
  • MGE can lose their independence during evolution but are retained if they acquire beneficial functions for the host.
  • This process, known as exaptation, leads to the vertical inheritance of formerly mobile elements.

Purpose of the Study:

  • To review the diversity of exapted MGE in prokaryotes.
  • To highlight the range of cellular functions acquired by these repurposed elements.
  • To explore the evolutionary entanglement of MGE and host defense systems.

Main Methods:

  • Literature review and synthesis of existing research on MGE exaptation in prokaryotes.
  • Analysis of examples illustrating the functional diversification of MGE.
  • Discussion of evolutionary factors influencing MGE exaptation.

Main Results:

  • Exapted MGE perform diverse cellular functions, significantly contributing to prokaryotic defense against viruses and other MGE.
  • Evolutionary similarities and shared challenges (e.g., host fitness costs) drive the entanglement of MGE and defense systems.
  • Factors such as MGE identity, mobility, and host relationship influence the exaptation process.

Conclusions:

  • Exaptation is a key evolutionary mechanism shaping prokaryotic genomes and functional systems.
  • The integration of MGE into host defense mechanisms highlights a co-evolutionary dynamic.
  • Understanding MGE exaptation provides insights into microbial adaptation and genome evolution.
Keywords:
antivirus defense mechanismsbiological conflict systemsexaptationhorizontal gene transfermobile genetic element

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