Pleiotropy: Difference between revisions

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'''Pleiotropy''' refers to the phenomenon where a single [[gene]] influences multiple, seemingly unrelated phenotypic traits. The term was first coined by the British geneticist [[Ludwig Plate]] in 1910. Pleiotropy is a fundamental aspect of [[genetics]] and is critical to our understanding of how genes function and interact within the [[genome]].
{{Short description|Concept in genetics where one gene influences multiple phenotypic traits}}


== Overview ==
'''Pleiotropy''' is a phenomenon in [[genetics]] where a single [[gene]] influences multiple, seemingly unrelated [[phenotypic traits]]. This concept is significant in understanding the complexity of genetic expression and its impact on [[organism]] development and function.


Pleiotropy occurs when a single gene impacts more than one phenotypic trait. This can happen in several ways. For instance, the gene might code for a product that is used by various cells or tissues in the body, or it might control several different reactions in the biochemical pathway.  
==Overview==
Pleiotropy occurs when one gene affects multiple traits. This can happen through various mechanisms, such as a gene product being involved in multiple biochemical pathways or a gene influencing a developmental process that affects multiple traits. The effects of pleiotropy can be seen in both [[morphological]] and [[physiological]] traits.


== Types of Pleiotropy ==
[[File:SimpleGenotypePhenotypeMap.jpg|Pleiotropy|thumb|right]]


There are two main types of pleiotropy: [[Antagonistic Pleiotropy]] and [[Synergistic Pleiotropy]].
==Mechanisms of Pleiotropy==
Pleiotropy can arise through several mechanisms:


=== Antagonistic Pleiotropy ===
* '''Biochemical Pathways''': A single enzyme or protein may participate in multiple biochemical pathways, affecting different traits.
* '''Developmental Pathways''': A gene may play a role in a developmental process that influences multiple traits.
* '''Gene Regulation''': A gene may regulate the expression of other genes, leading to a cascade of effects on various traits.


Antagonistic pleiotropy refers to the situation where a gene has a positive effect on one trait and a negative effect on another. This concept is central to the [[Evolutionary Theory of Aging]], which suggests that natural selection favors genes that enhance survival and reproduction early in life, even if those same genes have detrimental effects later in life.
==Examples of Pleiotropy==


=== Synergistic Pleiotropy ===
===Sickle Cell Anemia===
[[File:Red_Blood_Cells_in_Sickle_Cell_Disease.jpg|Red Blood Cells in Sickle Cell Disease|thumb|left]]
Sickle cell anemia is a classic example of pleiotropy. The mutation in the [[hemoglobin]] gene affects the shape of red blood cells, leading to various symptoms such as anemia, pain, and increased risk of infection.


Synergistic pleiotropy, on the other hand, occurs when a gene has a positive effect on two or more traits. This can lead to an increase in the fitness of an organism, as the beneficial effects of the gene are amplified across multiple traits.
===Marfan Syndrome===
[[File:Marfan_Patient.jpeg|Marfan syndrome patient|thumb|right]]
Marfan syndrome is caused by mutations in the [[FBN1]] gene, which encodes the protein fibrillin-1. This affects connective tissue throughout the body, leading to symptoms in the [[skeletal system]], [[cardiovascular system]], and [[ocular system]].


== Examples of Pleiotropy ==
===Phenylketonuria===
[[File:Phenylketonuria_testing.jpg|Phenylketonuria testing|thumb|left]]
Phenylketonuria (PKU) is a metabolic disorder caused by mutations in the [[PAH]] gene, which encodes the enzyme phenylalanine hydroxylase. This leads to the accumulation of phenylalanine, affecting brain development and causing intellectual disability if untreated.


One of the most well-known examples of pleiotropy is the [[sickle cell gene]]. This gene, when present in a single copy, provides resistance to [[malaria]]. However, when present in two copies, it causes [[sickle cell anemia]], a serious and often fatal disease.
===Albinism===
[[File:Pavo_cristatus_-Southwicks_Zoo,_Massachusetts,_USA_-albino-8a_(1).jpg|Albino peacock at Southwick's Zoo, Massachusetts, USA|thumb|right]]
Albinism is a condition characterized by a lack of pigment in the skin, hair, and eyes. It is caused by mutations in genes involved in melanin production, affecting multiple traits related to pigmentation and vision.


Another example is the [[phenylketonuria]] (PKU) gene. Individuals with two copies of this gene cannot metabolize the amino acid phenylalanine, leading to a buildup of toxic substances in the body. This can result in mental retardation, seizures, and other serious health problems.
==Implications of Pleiotropy==
Pleiotropy has significant implications in [[evolutionary biology]], [[medicine]], and [[genetic research]]. It can complicate the mapping of genotype to phenotype and influence the evolutionary fitness of organisms. In medicine, understanding pleiotropy is crucial for diagnosing and treating genetic disorders.


== Implications of Pleiotropy ==
==Related pages==
 
* [[Genetics]]
Pleiotropy has significant implications for [[genetic research]] and [[medicine]]. Understanding the pleiotropic effects of genes can help scientists develop more effective treatments for genetic diseases. It can also provide insights into the complex interactions between genes and the environment, and how these interactions influence health and disease.
* [[Phenotype]]
* [[Gene expression]]
* [[Genetic disorder]]


[[Category:Genetics]]
[[Category:Genetics]]
[[Category:Biology]]
[[Category:Biology]]
{{Genetics-stub}}
<gallery>
File:SimpleGenotypePhenotypeMap.jpg|Pleiotropy
File:Pleiotropic_overlap_between_polygenic_predictors_(in_variance_accounted_for).svg|Pleiotropy
File:Pavo_cristatus_-Southwicks_Zoo,_Massachusetts,_USA_-albino-8a_(1).jpg|Albino peacock at Southwick's Zoo, Massachusetts, USA
File:Phenylketonuria_testing.jpg|Phenylketonuria testing
File:Red_Blood_Cells_in_Sickle_Cell_Disease.jpg|Red Blood Cells in Sickle Cell Disease
File:Marfan_Patient.jpeg|Marfan syndrome patient
File:Salon_agriculture_2009_-_Padoue_frisée_blanche.jpg|Padoue frisée blanche chicken
</gallery>
<gallery>
File:SimpleGenotypePhenotypeMap.jpg|Pleiotropy
File:Pleiotropic overlap between polygenic predictors (in variance accounted for).svg|Pleiotropy
File:Pavo cristatus -Southwicks Zoo, Massachusetts, USA -albino-8a (1).jpg|Pleiotropy
File:Phenylketonuria testing.jpg|Pleiotropy
File:Red Blood Cells in Sickle Cell Disease.jpg|Pleiotropy
File:Marfan Patient.jpeg|Pleiotropy
File:Salon agriculture 2009 - Padoue frisée blanche.jpg|Pleiotropy
</gallery>

Latest revision as of 11:45, 23 March 2025

Concept in genetics where one gene influences multiple phenotypic traits


Pleiotropy is a phenomenon in genetics where a single gene influences multiple, seemingly unrelated phenotypic traits. This concept is significant in understanding the complexity of genetic expression and its impact on organism development and function.

Overview[edit]

Pleiotropy occurs when one gene affects multiple traits. This can happen through various mechanisms, such as a gene product being involved in multiple biochemical pathways or a gene influencing a developmental process that affects multiple traits. The effects of pleiotropy can be seen in both morphological and physiological traits.

Pleiotropy

Mechanisms of Pleiotropy[edit]

Pleiotropy can arise through several mechanisms:

  • Biochemical Pathways: A single enzyme or protein may participate in multiple biochemical pathways, affecting different traits.
  • Developmental Pathways: A gene may play a role in a developmental process that influences multiple traits.
  • Gene Regulation: A gene may regulate the expression of other genes, leading to a cascade of effects on various traits.

Examples of Pleiotropy[edit]

Sickle Cell Anemia[edit]

Red Blood Cells in Sickle Cell Disease

Sickle cell anemia is a classic example of pleiotropy. The mutation in the hemoglobin gene affects the shape of red blood cells, leading to various symptoms such as anemia, pain, and increased risk of infection.

Marfan Syndrome[edit]

Marfan syndrome patient

Marfan syndrome is caused by mutations in the FBN1 gene, which encodes the protein fibrillin-1. This affects connective tissue throughout the body, leading to symptoms in the skeletal system, cardiovascular system, and ocular system.

Phenylketonuria[edit]

Phenylketonuria testing

Phenylketonuria (PKU) is a metabolic disorder caused by mutations in the PAH gene, which encodes the enzyme phenylalanine hydroxylase. This leads to the accumulation of phenylalanine, affecting brain development and causing intellectual disability if untreated.

Albinism[edit]

Albino peacock at Southwick's Zoo, Massachusetts, USA

Albinism is a condition characterized by a lack of pigment in the skin, hair, and eyes. It is caused by mutations in genes involved in melanin production, affecting multiple traits related to pigmentation and vision.

Implications of Pleiotropy[edit]

Pleiotropy has significant implications in evolutionary biology, medicine, and genetic research. It can complicate the mapping of genotype to phenotype and influence the evolutionary fitness of organisms. In medicine, understanding pleiotropy is crucial for diagnosing and treating genetic disorders.

Related pages[edit]