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Related Experiment Video

Updated: Jul 4, 2026

Screening Foodstuffs for Class 1 Integrons and Gene Cassettes

Screening Foodstuffs for Class 1 Integrons and Gene Cassettes

Published on: June 19, 2015

Insights and inferences about integron evolution from genomic data.

Diana R Nemergut¹, Michael S Robeson, Robert F Kysela

¹Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, USA. nemergut@colorado.edu

|June 3, 2008

Summary

This summary is machine-generated.

Integrons, key to bacterial gene sharing, are widespread but often non-functional. Their varied presence suggests a dynamic evolutionary history influenced by environmental factors.

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Area of Science:

Microbiology
Genetics
Evolutionary Biology

Background:

Integrons are mobile genetic elements facilitating horizontal gene transfer in bacteria.
They play a crucial role in the dissemination of antibiotic resistance genes and other traits.
This study systematically analyzes the distribution and diversity of integron integrase (intI) genes.

Purpose of the Study:

To investigate the global distribution and diversity of integron intI genes across various bacterial species.
To understand the evolutionary dynamics and functional status of integrons in bacterial genomes.

Main Methods:

Bioinformatic analysis of publicly available genomic data.
Identification and characterization of intI genes and associated gene cassettes.
Phylogenetic analysis and dN/dS ratio calculations to assess evolutionary pressures.

Main Results:

Integrons were identified in 103 bacterial species across six phyla, showing a scattered distribution.
Approximately one-third of identified intI genes were pseudogenes, indicating loss of function.
Multiple integrase genes were found in 20% of bacteria, with specific mutational hotspots identified in Vibrio and Shewanella.

Conclusions:

The current distribution of integrons results from multiple gene loss and horizontal transfer events.
The high frequency of pseudogenes suggests that integron function can be deleterious, leading to selection against functional integrases.
The selective impact of integrons on bacterial genomes is variable and likely influenced by environmental conditions.