Aggressive behavior is shaped by both genetic variations and environmental factors. The MAOA gene, especially its low-activity variant MAOA-L, is linked to increased aggression, particularly when combined with adverse environmental conditions like childhood abuse. Twin and adoption studies, along with animal research, underscore the genetic basis of aggression while emphasizing the importance of environmental influences in its manifestation.
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The MAOA gene, which encodes an enzyme that metabolizes neurotransmitters, has been linked to aggressive behavior
Low-activity form (MAOA-L)
The low-activity variant of the MAOA gene has been associated with increased aggression, especially when combined with environmental factors like childhood abuse
High-activity form (MAOA-H)
The high-activity variant of the MAOA gene may have a protective effect against aggressive behavior
Twin and adoption studies suggest a genetic contribution to aggression, with monozygotic twins showing a higher concordance for aggressive behavior
Environmental factors such as upbringing and social interactions play a critical role in shaping the expression of genetic predispositions for aggressive behavior
High levels of stress can exacerbate genetic predispositions for aggressive behavior
Traumatic experiences during formative years can increase the risk of developing aggressive behavior, particularly in individuals with the MAOA-L variant
Selective breeding experiments in animals have shown that certain aspects of aggressive behavior can be inherited
Differences in species-specific behavior must be considered when extrapolating results from animal studies to humans
The MAOA-L variant has been linked to an increased risk of developing psychopathic traits, particularly when combined with early life stressors
Individuals with the MAOA-L variant may exhibit differences in brain structure and function, suggesting a role of genetics in the development of psychopathy
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MAOA gene function
Encodes enzyme metabolizing neurotransmitters like serotonin, dopamine.
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MAOA-L variant and aggression
Low-activity MAOA gene form linked to increased aggression.
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Aggression: Genetic vs. Environmental factors
Aggression most predicted by genetic susceptibility combined with adverse environments.
