Related Experiment Video
Updated: Feb 2, 2026
15:00
Daily Transfers, Archiving Populations, and Measuring Fitness in the Long-Term Evolution Experiment with Escherichia coli
Published on: August 18, 2023
4.3K
Evolution of Bacterial Gene Transfer Agents
Rosemary J Redfield1, Shannon M Soucy2
1Department of Zoology, University of British Columbia, Vancouver, BC, Canada.
Frontiers in Microbiology
|November 10, 2018
Summary
Bacterial gene transfer agents (GTAs) package DNA but their genes are not maintained by direct transfer or chromosomal recombination. Alternative selective benefits must explain their long-term persistence.
Area of Science:
- Microbiology
- Evolutionary Biology
- Genetics
Background:
- Bacterial gene transfer agents (GTAs) are virus-like particles delivering DNA fragments into cells.
- GTA gene clusters, resembling defective prophages, are thought to be maintained by selection for GTA-mediated recombination.
- Previous hypotheses lack rigorous testing regarding the selective advantages of GTAs.
Purpose of the Study:
- To rigorously examine the potential benefits of GTA-mediated recombination for maintaining GTA gene clusters.
- To differentiate between direct transmission of GTA genes and recombination of chromosomal genes.
- To identify conditions under which GTA-producing populations exhibit higher fitness.
Main Methods:
- Theoretical examination of direct GTA gene transmission versus chromosomal gene recombination.
- Development of a simulation model to assess population fitness under various conditions.
- Analysis of fitness benefits considering synergistic epistasis and regulatory modes.
Main Results:
- Direct transmission of GTA genes cannot compensate for the cost of cell lysis and inefficient replication.
- While recombination of chromosomal genes can provide fitness benefits, these are insufficient for GTA+ invasion or resistance.
- Observed benefits rely on improbable assumptions regarding GTA production and recombination efficiencies.
Conclusions:
- The long-term maintenance of GTA gene clusters is unlikely to be driven by direct gene transfer or chromosomal recombination.
- Alternative, yet unidentified, selective benefits must account for the evolutionary persistence of bacterial GTAs.
- This study challenges existing assumptions about the evolutionary drivers of GTA systems.
Related Concept Videos
03:21Genome Size and the Evolution of New Genes
9.1K
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.
9.1K
03:21Genome Size and the Evolution of New Genes
3.4K
3.4K
02:05Gene Evolution - Fast or Slow?
8.2K
The genomes of eukaryotes are punctuated by long stretches of sequence which do not code for proteins or RNAs. Although some of these regions do contain crucial regulatory sequences, the vast majority of this DNA serves no known function. Typically, these regions of the genome are the ones in which the fastest change, in evolutionary terms, is observed, because there is typically little to no selection pressure acting on these regions to preserve their sequences.
In contrast, regions which code...
In contrast, regions which code...
8.2K
02:05Gene Evolution - Fast or Slow?
3.7K
3.7K
01:27Horizontal Gene Transfer
2.2K
Horizontal gene transfer (HGT) is a process where genetic material moves between organisms within the same generation, unlike vertical gene transfer, which occurs from parent to offspring. HGT plays a crucial role in microbial evolution, adaptation, and survival, particularly in shared environments like the human gut.Mobile genetic elements such as plasmids, prophages, integrons, insertion sequences, and transposons facilitate this process. HGT occurs through three primary mechanisms:...
2.2K
02:55The Evidence for Evolution
48.2K
Genetic variations accumulating within populations over generations give rise to biological evolution. Evolutionary changes can result in the formation of novel varieties and entire new species. These changes are responsible for the diverse forms of life inhabiting the planet. The evidence for evolution suggests that all living organisms descended from common ancestors.
48.2K