Related Experiment Video
Updated: Jun 3, 2026
06:59
A Reverse Genetic Approach to Test Functional Redundancy During Embryogenesis
Published on: August 11, 2010
Loss of genetic redundancy in reductive genome evolution
André G Mendonça1, Renato J Alves, José B Pereira-Leal
1Instituto Gulbenkian de Ciência, Oeiras, Portugal.
Plos Computational Biology
|March 8, 2011
Summary
Biological systems maintain robustness through genetic redundancy. In predictable environments, reduced genomes prioritize protein family diversity over gene duplicates, suggesting a loss of redundancy due to decreased selection for robustness.
Area of Science:
- Evolutionary biology
- Genomics
Background:
- Biological systems exhibit functional robustness and adaptability.
- Genetic redundancy, through duplicate genes, enhances robustness against mutations or environmental stress.
- Highly variable environments favor robustness, while predictable environments may not.
Purpose of the Study:
- To investigate the evolutionary dynamics of genetic redundancy in reduced genomes.
- To test the hypothesis that predictable environments reduce the selective pressure for robustness.
- To understand gene loss patterns in intracellular parasites and endosymbionts.
Main Methods:
- Analysis of extensive gene loss in reduced genomes.
- Simulations of genome evolution.
- Comparative genomics of protein family diversity and gene duplication (paralogy).
Main Results:
- Reduced genomes selectively retain protein family diversity while losing paralogs.
- This pattern is not a byproduct of known genome reduction drivers.
- Limited convergence on a common set of protein families across reduced genomes.
Conclusions:
- Reduced genomes show a loss of genetic redundancy.
- This loss is linked to decreased selection for robustness in predictable environments.
- The repertoire of protein families is shaped by historical contingency and niche adaptation.
Related Concept Videos
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.
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...
02:37Gene Duplication and Divergence
The seminal work of Ohno in 1970 popularized the idea of gene duplication and divergence. DNA sequence comparison studies reveal that a large portion of the genes in bacteria, archaebacteria, and eukaryotes was generated by gene duplication and divergence, indicating its critical role in evolution.
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are characterized.
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are characterized.
03:21Genome 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.
03:21Genome 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.