Related Experiment Video
Updated: May 8, 2026
14:06
Mapping Bacterial Functional Networks and Pathways in Escherichia Coli using Synthetic Genetic Arrays
Published on: November 12, 2012
Hard selective sweep and ectopic gene conversion in a gene cluster affording environmental adaptation
Marc Hanikenne1, Juergen Kroymann, Aleksandra Trampczynska
1Functional Genomics and Plant Molecular Imaging, Center for Protein Engineering, CIP, Department of Life Sciences, University of Liège, Liège, Belgium.
Plos Genetics
|August 31, 2013
Summary
Arabidopsis halleri
Area of Science:
- Plant biology
- Genomics
- Evolutionary biology
Background:
- Arabidopsis halleri is a model extremophile adapted to toxic soils.
- Metal hypertolerance in A. halleri relies on Heavy Metal ATPase4 (HMA4).
- Previous studies focused on single A. halleri accessions.
Purpose of the Study:
- Investigate nucleotide sequence polymorphism in the HMA4 genomic region.
- Understand the evolutionary mechanisms of HMA4 adaptation.
- Examine the role of gene copy number and regulatory modifications.
Main Methods:
- Sequencing of 13 DNA segments across the HMA4 genomic region in multiple A. halleri individuals.
- Analysis of nucleotide sequence diversity and polymorphism patterns.
- Quantitative PCR to measure HMA4 transcript levels.
Main Results:
- Positive selection identified in HMA4 promoter regions, particularly HMA4-3.
- Gene conversion among HMA4 coding sequences led to concerted evolution and network-like genealogy.
- Three HMA4 copies result in 20- to 130-fold higher transcript levels compared to A. thaliana.
- Complex polymorphism profile observed due to natural selection for increased gene product dosage.
Conclusions:
- Enhanced gene product dosage is a key mechanism for genomic maintenance of gene duplicates in environmental adaptation.
- Findings provide a paradigm for multi-copy genes in adaptation across diverse organisms.
- Recurrent gene conversion and selection on promoter regions shape the evolution of multi-copy genes.
More Related Videos
Related Concept Videos
02:08Gene Conversion
Other than maintaining genome stability via DNA repair, homologous recombination plays an important role in diversifying the genome. In fact, the recombination of sequences forms the molecular basis of genomic evolution. Random and non-random permutations of genomic sequences create a library of new amalgamated sequences. These newly formed genomes can determine the fitness and survival of cells. In bacteria, homologous and non-homologous types of recombination lead to the evolution of new...
02:08Gene Conversion
Other than maintaining genome stability via DNA repair, homologous recombination plays an important role in diversifying the genome. In fact, the recombination of sequences forms the molecular basis of genomic evolution. Random and non-random permutations of genomic sequences create a library of new amalgamated sequences. These newly formed genomes can determine the fitness and survival of cells. In bacteria, homologous and non-homologous types of recombination lead to the evolution of new...
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...
02:53Conservative Site-specific Recombination and Phase Variation
Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...
The recognition sites for Cre recombinase called LoxP...
01:16Transduction
Among the three main modes of HGT—transformation, conjugation, and transduction—transduction is unique in that it is mediated by bacteriophages, or bacterial viruses.Transduction occurs in two ways. Generalized transduction occurs during the lytic cycle of a bacteriophage infection. In this process, bacteriophages infect bacterial cells, replicate within them, and ultimately cause cell lysis, releasing newly assembled virions. Occasionally, random fragments of the bacterial genome are...
02:32Exon Recombination
The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes.
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Exon shuffling follows “splice frame rules.” Each exon has three reading...