genetic Explanations Flashcards
What are the two types of MAOA gene and how do they differ?
1) low activity form (MAOA-L). People with this produce less of the MAO enzyme hence they do not remove as much dopamine and serotonin.
2) high activity form (MAOA-H) produce more of enzyme hence remove more dopamine and serotonin.
People with low form are thought to have more aggressive tendencies.
What did Cases et al find supporting MAOA gene theory?
Studied mice genetically engineered to lack MAOA gene. Found that the mice had dramatically altered levels of serotonin and showed enhanced aggression when adult males.
What did Mattson find similar to Cases?
Found that MAOA deficient male mice attacked new mice introduced to their cage. Female mice with the defective gene behaved normally suggesting the effect may only be inherited in males.
What did Brunner find supporting MAOA GENE?
Discovered a defective MAOA gene in a Dutch history with a previous history of male violence. Suggests that defective MAOA gene also plays a role in human aggression.
What did Moffit find criticising this?
Found that aggressive behaviour was 9x more likely in participants with MAOA-L gene if they had suffered abuse as children. participants who suffered abuse with MAOA-H were no more likely to behave aggressively than a control group suffering no abuse.
Outline the MAOA gene and its link to aggression:
MAOA (monoamine oxidase A) regulates the enzyme MOA (monoamine oxidase A) this enzyme breaks down neurotransmitters like serotonin and dopamine which are associated with mood. A build up of these neurotransmitters can cause a person to respond aggressively to situations. MAOA gene regulates the enzyme which removes excess amounts of these neurotransmitters.
