A variant of the X-linked MAOA gene, also known as the “warrior gene”, has been associated with increased aggressive behavior in people who experienced abuse as children. The MAOA gene codes for a protein enzyme called monoamine oxidase A (MAOA), which breaks down the neurotransmitters serotonin, dopamine, and noradrenaline, and thus can influence mood and behavior. The warrior variant of this gene is about 30 bases shorter and causes a lower production of the enzyme.
Some recent court cases have allowed for the inclusion of genetic analysis for the warrior gene. In two such cases, the result of these analyses have lead to reduced sentences for individuals convicted of excessively violent crimes who also had the warrior gene. Please read the following news articles explaining how genetic analysis of the warrior gene influenced sentencing in these court cases.
Based on what you know about this gene, the information in these articles, and what you’ve learned by working through the assigned material in chapters 5-8, please discuss the following questions:
1. Describe all of the ways that the trait of aggressive behavior deviates from traditional Mendelian inheritance patterns.
2. Should genetic analysis of the warrior gene or other such genes associated with behavior be used to influence criminal sentencing in court cases? Explain why or why not.
3. What could be a limitation to the use of behavioral genotyping information in a criminal trial?