Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Evolution of Microbial Genome

Evolution of Microbial Genome

Microbial genome evolution is a highly dynamic process shaped by continual gene gain and loss across species and strains. This genomic flexibility allows microorganisms to adapt rapidly to environmental pressures and interactions with other organisms. Central to understanding this diversity is the distinction between the core and pan genomes.The core genome comprises the genes shared by all sampled strains of a species, representing essential functions needed for fundamental cellular processes.

Genome Size and the Evolution of New Genes

Genome Size and the Evolution of New Genes

While every living organism has a genome of some kind (be it RNA, or DNA), there is considerable variation in the sizes of these blueprints. One major factor that impacts genome size is whether the organism is prokaryotic or eukaryotic. In prokaryotes, the genome contains little to no non-coding sequence, such that genes are tightly clustered in groups or operons sequentially along the chromosome. Conversely, the genes in eukaryotes are punctuated by long stretches of non-coding sequence.

Genome Size and the Evolution of New Genes

Genome Size and the Evolution of New Genes

While every living organism has a genome of some kind (be it RNA, or DNA), there is considerable variation in the sizes of these blueprints. One major factor that impacts genome size is whether the organism is prokaryotic or eukaryotic. In prokaryotes, the genome contains little to no non-coding sequence, such that genes are tightly clustered in groups or operons sequentially along the chromosome. Conversely, the genes in eukaryotes are punctuated by long stretches of non-coding sequence.

Genomic DNA in Prokaryotes

Genomic DNA in Prokaryotes

The genome of most prokaryotic organisms consists of double-stranded DNA organized into one circular chromosome in a region of cytoplasm called the nucleoid. The chromosome is tightly wound, or supercoiled, for efficient storage. Prokaryotes also contain other circular pieces of DNA called plasmids. These plasmids are smaller than the chromosome and often carry genes that confer adaptive functions, such as antibiotic resistance.
Genomic Diversity in Bacteria
Although bacterial genomes are much...

Modern Molecular Taxonomy

Modern Molecular Taxonomy

Advancements in molecular biology have revolutionized the identification and characterization of bacteria, with multiple methods leveraging DNA sequencing for enhanced precision. As sequencing technologies improve and costs decline, these approaches are increasingly used in clinical, environmental, and evolutionary studies.Multilocus Sequence Typing (MLST) examines several housekeeping genes, essential chromosomal genes encoding cellular functions, to distinguish strains. Approximately...

Evolutionary Processes in Microbes

Evolutionary Processes in Microbes

Microbial evolution occurs rapidly due to short generation times and a variety of genetic processes, including horizontal gene transfer, mutation, recombination, and genetic drift. These mechanisms collectively enable microbes to adapt swiftly to changing environments.Horizontal gene transfer (HGT) allows genes to move between different species and occurs through three main mechanisms: conjugation, transformation, and transduction. Conjugation involves direct cell-to-cell contact for DNA...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Modular small RNA drives the emergence of virulence traits and environmental trade-offs in Vibrio cholerae.

Nature communications·2026

Same author

Deciphering the evolutionary history of ectoine catabolism, a compatible solute utilized by <i>Vibrio diabolicus</i> as an osmoprotectant and a nutrient source.

Applied and environmental microbiology·2026

Same author

Bile-mediated ToxS homodimerization provides a model for ToxRS periplasmic interactions.

bioRxiv : the preprint server for biology·2026

Same author

Allelic variations and gene cluster modularity act as nonlinear bottlenecks for cholera emergence.

Proceedings of the National Academy of Sciences of the United States of America·2025

Same author

Dual roles of glycine betaine, dimethylglycine, and sarcosine as osmoprotectants and nutrient sources for <i>Vibrio natriegens</i>.

Applied and environmental microbiology·2025

Same author

Dual roles of glycine betaine (GB), dimethylglycine, and sarcosine as osmoprotectants and nutrient sources for <i>Vibrio natriegens</i>.

bioRxiv : the preprint server for biology·2025

Search research articles

Related Experiment Video

Updated: Jun 26, 2026

Following the Dynamics of Structural Variants in Experimentally Evolved Populations

Following the Dynamics of Structural Variants in Experimentally Evolved Populations

Published on: February 3, 2023

Genomic islands are dynamic, ancient integrative elements in bacterial evolution.

E Fidelma Boyd¹, Salvador Almagro-Moreno, Michelle A Parent

¹Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA. fboyd@udel.edu

Trends in Microbiology

|January 24, 2009

Summary

Genomic islands drive bacterial evolution and adaptation by integrating new genes. These ancient elements, distinct from plasmids and phages, preferentially insert into tRNA genes in Gram-negative bacteria.

More Related Videos

Mapping Bacterial Functional Networks and Pathways in Escherichia Coli using Synthetic Genetic Arrays

Mapping Bacterial Functional Networks and Pathways in Escherichia Coli using Synthetic Genetic Arrays

Published on: November 12, 2012

Heuristic Mining of Hierarchical Genotypes and Accessory Genome Loci in Bacterial Populations

Heuristic Mining of Hierarchical Genotypes and Accessory Genome Loci in Bacterial Populations

Published on: December 7, 2021

Related Experiment Videos

Last Updated: Jun 26, 2026

Following the Dynamics of Structural Variants in Experimentally Evolved Populations

Following the Dynamics of Structural Variants in Experimentally Evolved Populations

Published on: February 3, 2023

Mapping Bacterial Functional Networks and Pathways in Escherichia Coli using Synthetic Genetic Arrays

Mapping Bacterial Functional Networks and Pathways in Escherichia Coli using Synthetic Genetic Arrays

Published on: November 12, 2012

Heuristic Mining of Hierarchical Genotypes and Accessory Genome Loci in Bacterial Populations

Heuristic Mining of Hierarchical Genotypes and Accessory Genome Loci in Bacterial Populations

Published on: December 7, 2021

Area of Science:

Bacterial Genetics
Evolutionary Biology
Genomics

Background:

Genomic islands are key drivers of bacterial evolution, facilitating adaptation and diversification.
These elements are non-self-mobilizing and integrate into the host genome, encoding various functions.
All genomic islands possess a recombination module, including an integrase and attachment sites.

Purpose of the Study:

To investigate the evolutionary origin of a specific group of genomic islands.
To differentiate these genomic islands from other mobile genetic elements like plasmids and phages.
To analyze the diversity and insertion site preferences of genomic islands in Gram-negative bacteria.

Main Methods:

Comparative genomics analysis.
Phylogenetic reconstruction to determine evolutionary relationships.
Bioinformatic analysis of insertion site distribution.

Main Results:

A group of related genomic islands were identified as evolutionarily ancient and distinct from plasmids, phages, integrons, and integrative conjugative elements.
Significant diversity in genomic islands and their insertion sites was observed among Gram-negative bacteria.
Genomic islands were found to integrate preferentially at a limited set of tRNA genes.

Conclusions:

Genomic islands represent ancient, non-mobile genetic elements crucial for bacterial adaptation.
Their integration at specific tRNA loci suggests a conserved mechanism and potential functional significance in Gram-negative bacteria.