Related Experiment Video
Updated: Jul 19, 2026
08:11
Adaptation at the Extremes of Life: Experimental Evolution with the Extremophile Archaeon Sulfolobus acidocaldarius
Published on: June 14, 2024
Evolution of competence and DNA uptake specificity in the Pasteurellaceae
Rosemary J Redfield1, Wendy A Findlay, Janine Bossé
1Dept. of Zoology, University of British Columbia, Vancouver, BC, Canada. redfield@zoology.ubc.ca
BMC Evolutionary Biology
|October 14, 2006
Summary
Natural competence and DNA uptake specificity are ancient traits in Pasteurellaceae bacteria. Divergent uptake signal sequences (USS) distinguish major lineages, suggesting competence loss may lead to evolutionary dead ends.
Area of Science:
- Microbiology
- Evolutionary Biology
- Genetics
Background:
- The evolutionary history and function of natural competence and transformation in bacteria are not well understood.
- The sporadic distribution of competence suggests frequent gain and loss, necessitating phylogenetic examination.
- DNA uptake specificity, exemplified by the 9 bp uptake signal sequence (USS) in *Haemophilus influenzae*, offers clues to competence evolution.
Purpose of the Study:
- To investigate the evolutionary history and ancestry of natural competence within the Pasteurellaceae family.
- To analyze the distribution of competence genes and DNA uptake specificity across Pasteurellaceae species.
- To determine the phylogenetic context of competence gene presence and loss.
Main Methods:
- Phylogenetic analysis of 12 protein-coding genes from sequenced Pasteurellaceae genomes.
- Identification and comparison of competence gene homologues across species.
- Analysis of uptake signal sequence (USS) distribution, consensus, and flanking regions.
- DNA uptake and competition experiments to assess uptake specificity.
Main Results:
- A robust phylogeny revealed two main subclades: Hin and Apl.
- All examined species possess homologues of known competence genes, indicating ancestral competence.
- Competence gene defects were recent in three species (*H. somnus*, *H. ducreyi*, *M. haemolytica*).
- Distinct USS consensus sequences were identified for Hin (AAGTGCGGT) and Apl (ACAAGCGGT) subclades, with conserved flanking AT-rich regions.
- Experimental data confirmed the Apl-type repeat as a functional USS, with species showing preferential uptake of their cognate USS.
Conclusions:
- Natural competence and DNA uptake specificity are ancestral traits within the Pasteurellaceae.
- Divergent USS sequences and uptake specificities distinguish the two major Pasteurellaceae subclades.
- The long-term conservation of competence genes suggests that loss of competence may represent an evolutionary disadvantage.
Related Concept Videos
01:24Evolution of New Traits in Microbes
Microorganisms evolve rapidly due to their large population sizes and short generation times, often exhibiting measurable changes within days under laboratory conditions. Natural selection acts on standing genetic variation, enabling the retention and amplification of beneficial traits that confer fitness advantages in changing environments.Adaptive Pigment Regulation in RhodobacterIn Rhodobacter, a genus of purple non-sulfur bacteria, light-harvesting pigments such as bacteriochlorophyll and...
01:26Transformation
Microbial communities are dynamic environments where cell lysis releases free DNA into the surroundings. Other cells can take up this extracellular DNA through a process known as transformation.When a cell incorporates this foreign DNA into its genome, resulting in genetic modification, the process is known as transformation. Cells capable of this process are termed competent. Competence can be natural, as observed in certain bacteria and archaea, or artificially induced in the...
01:33Bacterial Transformation
In 1928, bacteriologist Frederick Griffith worked on a vaccine for pneumonia, which is caused by Streptococcus pneumoniae bacteria. Griffith studied two pneumonia strains in mice: one pathogenic and one non-pathogenic. Only the pathogenic strain killed host mice.Griffith made an unexpected discovery when he killed the pathogenic strain and mixed its remains with the live, non-pathogenic strain. Not only did the mixture kill host mice, but it also contained living pathogenic bacteria that...
01:08Evolution 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.
00:57Antibiotic Selection
Overview
01:26Evolutionary 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...