Robustness (evolution)
Encyclopedia
Robustness of a biological system
(i.e. biological robustness ) is the persistence of a certain characteristic or trait in a system under perturbations or conditions of uncertainty. Robustness in development is known as canalization
. According to the kind of perturbation involved, robustness can be classified as mutational robustness
, environmental robustness, recombinational robustness, behavioral robustness , etc.
regulatory complexity in gene regulatory networks;
Degeneracy
that arises in protein interactions, in signalling networks (crosstalk), and metabolic pathways; Saturation effects that arise in many metabolic pathways involving enzymes with high catalytic activity; Spatial and temporal modularity during RNA folding.. From a situated, embodied and dynamical systems perspective, current discussions are rooted on mechanisms for robust behavior that distribute between internal control (brain), body and environment
, have also been applied to study robustness.
Biological system
In biology, a biological system is a group of organs that work together to perform a certain task. Common systems, such as those present in mammals and other animals, seen in human anatomy, are those such as the circulatory system, the respiratory system, the nervous system, etc.A group of systems...
(i.e. biological robustness ) is the persistence of a certain characteristic or trait in a system under perturbations or conditions of uncertainty. Robustness in development is known as canalization
Canalisation (genetics)
Canalisation is a measure of the ability of a population to produce the same phenotype regardless of variability of its environment or genotype. In other words, it means robustness. The term canalisation was coined by C. H. Waddington...
. According to the kind of perturbation involved, robustness can be classified as mutational robustness
Mutational robustness
Mutational robustness describes the extent to which an organism’s phenotype remains constant in spite of mutation. Natural selection can directly induce the evolution of mutational robustness only when mutation rates are high and population sizes are large...
, environmental robustness, recombinational robustness, behavioral robustness , etc.
Importance
Since organisms are constantly exposed to genetic and non-genetic perturbations, robustness is important to ensure the stability of phenotypes. Also, under mutation-selection balance, mutational robustness allows genetic differences to accumulate in a population. While phenotypically cryptic in a stable environment, these genetic differences can be revealed as trait differences in an environment-dependent manner (see cryptic genetic variation), thereby allowing for the expression of a greater number of heritable phenotypes in populations exposed to a variable environment.Mechanisms
Many mechanisms and system properties are positively associated with robust traits in biological systems. These include:regulatory complexity in gene regulatory networks;
Degeneracy
Degeneracy (biology)
Within biological systems, degeneracy refers to circumstances where structurally dissimilar components/modules/pathways can perform similar functions under certain conditions, but perform distinct functions in other conditions. Degeneracy is thus a relational property that requires comparing the...
that arises in protein interactions, in signalling networks (crosstalk), and metabolic pathways; Saturation effects that arise in many metabolic pathways involving enzymes with high catalytic activity; Spatial and temporal modularity during RNA folding.. From a situated, embodied and dynamical systems perspective, current discussions are rooted on mechanisms for robust behavior that distribute between internal control (brain), body and environment
Model systems
There are many systems that have been used to study robustness. For example, RNA virus fitness, RNA secondary structure, bacterial chemotaxis, Drosophila segment polarity network, Drosophila core neurogenic network, Drosophila BMP morphogen gradient, C. elegans vulval development and mammalian circadian clock. Quantitative models, such as Wagner's gene network modelWagner's gene network model
Wagner's gene network model is a computational model of artificial gene networks, which explicitly modeled the developmental and evolutionary process of genetic regulatory networks. A population with multiple organisms can be created and evolved from generation to generation...
, have also been applied to study robustness.
See also
- EvolvabilityEvolvabilityEvolvability is defined as the capacity of a system for adaptive evolution. Evolvability is the ability of a population of organisms to not merely generate genetic diversity, but to generate adaptive genetic diversity, and thereby evolve through natural selection.In order for a biological organism...
- CanalizationCanalisation (genetics)Canalisation is a measure of the ability of a population to produce the same phenotype regardless of variability of its environment or genotype. In other words, it means robustness. The term canalisation was coined by C. H. Waddington...
- EpistasisEpistasisIn genetics, epistasis is the phenomenon where the effects of one gene are modified by one or several other genes, which are sometimes called modifier genes. The gene whose phenotype is expressed is called epistatic, while the phenotype altered or suppressed is called hypostatic...
- Fitness landscapeFitness landscapeIn evolutionary biology, fitness landscapes or adaptive landscapes are used to visualize the relationship between genotypes and reproductive success. It is assumed that every genotype has a well-defined replication rate . This fitness is the "height" of the landscape...
- Evolutionary developmental biologyEvolutionary developmental biologyEvolutionary developmental biology is a field of biology that compares the developmental processes of different organisms to determine the ancestral relationship between them, and to discover how developmental processes evolved...