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The surprising cooperation of two mutant genes: How does it change our understanding of genetics?
In the world of biology, the interaction of genes can be quite mysterious and complex. Gene interaction networks represent the functional interactions between two genes, which not only help us understand the relationship between genotype and phenotype, but also reveal many secrets about human genetics. Most genes do not code for a specific phenotype, but rather the interaction of multiple genes jointly influences the formation of the phenotype.
"Each individual carries approximately 4 million genetic variants and polymorphisms, the vast majority of which cannot be directly attributed to being the independent cause of a particular phenotype."
Studies have shown that interactions between genetic variants and environmental conditions may largely determine the phenotype produced by a genotype. Therefore, understanding gene interaction networks can provide valuable insights and help unravel the mechanisms of complex diseases. However, direct mapping of genetic interaction networks in humans has been impossible due to the inability to isolate subjects with single genetic variants. Researchers hope that by understanding the characteristics of genetic interaction networks in suitable organisms, they can provide tools for building genetic interaction networks in humans.
Overview of Genetic Interactions
Genetic interactions occur when the interaction between two or more genes causes a phenotype to differ from what is expected. For example, a strong phenotype usually indicates low fitness, whereas a weak phenotype may be close to the fitness of the non-mutant strain. A common phenotype for studying genetic interactions is fitness, which measures the relative reproductive rates of mutants.
“A genetic interaction is defined as the difference between the experimentally measured double mutant phenotype and the expected double mutant phenotype.”
The phenotype of a double mutant can manifest as either a negative genetic interaction or a positive genetic interaction. Negative genetic interactions occur when the phenotype of a double mutant is stronger than expected, while a special case is a synthetic lethal interaction, when removal of a single gene does not significantly harm the organism, but removal of both genes renders the organism nonviable. Alternatively, a positive genetic interaction means that the phenotype of the double mutant is weaker than expected. The criteria for measuring interactions between genes need to be based on the phenotypes when the genes are not expected to interact. Common models include the minimum model, additive model, and multiplicative model. Among them, when fitness is used as a phenotype, the multiplicative model performs best.
Characteristics of genetic interaction networks
Genetic interaction networks have been extensively studied in several organisms, such as yeast, Escherichia coli, nematodes, and fruit flies. These studies reveal the topological structure of genetic interaction networks, how they provide information about gene function, and the evolutionarily conserved nature of these networks. The researchers hope that by understanding the general properties of genetic interaction networks and combining them with other biological information, such as protein interaction networks, they can infer genetic interaction networks of other organisms such as humans.
"The hubs of genetic interaction networks are often essential proteins, and these interactions provide information about the functional relevance of two genes."
Gene interaction profiles support the construction of gene similarity networks that can predict the functions of uncharacterized genes. Some studies have explored how to analyze the conservation of these genetic networks over evolutionary distances. Although it is not yet clear how conserved individual gene interactions are, general properties of genetic interaction networks appear to be conserved, including the functions of network hubs and genetic interaction profiles. Predictive capabilities.
Biological significance
Understanding genetic interactions is crucial to linking genotype to phenotype. For example, genetic interactions have been proposed as an explanation for missing heritability. Missing heritability means that the genetic sources of many heritable phenotypes have not yet been discovered. Given that genetic interactions may extend beyond pairwise interactions between genes, they have the greatest potential to enhance the explanatory power of known gene origins, thus helping to reduce the challenges posed by missing heritability.
As we continue to explore the network of gene interactions, we may find more answers to the mysteries of genetics. How will these answers affect our understanding of ourselves?
