Pleiotropy
This article deals with the pleiotropy of genes; for several effects of a drug, see pleiotropy (pharmacology).
Pleiotropy (from ancient Greek πλείων pleíōn, German 'more' and ancient Greek τροπή tropē, German 'turn, change, alteration') is used in genetics and pharmacology as a technical term with slightly different definitions. In genetics, pleiotropy or polypheny (from ancient Greek πολυφανής polyphanēs, German 'multiple appearing') is the expression of different phenotypic traits caused by a single gene. Significant here, in distinction to syndromology, is that different mutations in a gene can cause different traits. This makes it possible that mutations in one and the same gene cause different diseases, which in turn are defined by the phenotype. The counterpart to pleiotropy is heterogeneity, in which the same phenotype is caused by mutations in different genes, but in a monogenic manner.
As an antagonistic pleiotropy plays a central role in the current understanding of the aging process. Pleiotropic effects of defective genes also play a role in many hereditary diseases. In pharmacology, pleiotropy refers to multiple effects of a drug. Pleiotropic effects of HMG-CoA reductase inhibitors (lipid-lowering drugs) affect, for example, endothelial function, the inflammatory response and blood coagulation, in addition to lowering cholesterol levels.
Polypheny can be a problem in the production of genetically modified organisms, because a foreign gene can, under certain circumstances, cause further effects in the recipient organism in addition to the desired trait. In particular, genetic manipulation of higher organisms, whose genomes are very complexly organized, can result in unpredictable polypheny effects.
See also
- Polyphenism
Questions and Answers
Q: What is pleiotropism?
A: Pleiotropism is a term used in developmental genetics where a single gene affects multiple phenotypic traits in the same organism.
Q: Are the pleiotropic effects related to each other?
A: The pleiotropic effects often seem unrelated to each other.
Q: What is the usual underlying mechanism of pleiotropism?
A: The usual underlying mechanism is that the same gene is activated in several different tissues, producing different effects.
Q: Is pleiotropism a common phenomenon?
A: Yes, pleiotropism is an extremely common phenomenon since most genes will have effects in more than one tissue.
Q: What is the difference between pleiotropism and pleiomorphism?
A: Pleiotropism is when a single gene affects multiple phenotypic traits in the same organism, whereas pleiomorphism is when a genetically uniform group of organisms shows variable phenotypes.
Q: Is pleiotropism a term used in other fields of study?
A: While pleiotropism is primarily used in developmental genetics, it has also been studied in other fields such as evolutionary biology.
Q: Can pleiotropism be observed in humans?
A: Yes, pleiotropism has been observed in humans, particularly in the context of genetic disorders where a single gene mutation affects multiple aspects of health.
