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Behavioral genetic research
Effect of heredity on human behaviors
Role genetics versus environment plays in our behavior
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In the field of genetics, the study of the effect of various genes is imperative in translation and interpretation. As genetic coding influences phenotypic expression, the analysis of specific genes and any polymorphisms are relevant in a clinical setting. One such example is that of personality traits, which are believed to be influenced by specific neurotransmitters, known as catecholamines. Catecholamines are chemicals released by the adrenal glands in response to stress, and operate dually as hormones and neurotransmitters within the body. Commonly, catecholamines mediate functions within the central nervous system, including those of emotional responses and motor control. Inclusive of dopamine, epinephrine and norepinephrine, the secretion and metabolism of these chemicals is thought to impact upon various mental functions and behaviours. The Catechol-O-methyltransferase (COMT) gene is a specialised type of enzyme, which is involved in the degradative processes of catecholamines. This process is a necessity in the human body, as prolonged exposure to catecholamines is detrime...
In the lab, Inhibiting the Action of Catechol Oxidase we had to investigate what type of enzyme inhibition occurs when an inhibitor is added. Catechol oxidase is an enzyme in plants that creates benzoquinone.Benzoquinone is a substance that is toxic to bacteria. It is brown and is the reason fruit turns brown. Now, there are two types of inhibitors, the competitive inhibitor and non-competitive inhibitor. For an enzyme reaction to occur a substrate has to bind or fit into the active site of the enzyme. In competitive inhibition there is a substrate and an inhibitor present, both compete to bind to the active site. If the competitive inhibitor binds to the active site it stops the reaction. A noncompetitive inhibitor binds to another region
Brunner and his colleagues, and upon the discovery of a particular genetic defect in male members of a large Dutch family. In this large Dutch kindred, Brunner et al. (1993) identified a novel form of X-linked nondysmorphic mild mental retardation, and he found that all of the male family members with this defect reacted aggressively when angry, fearful, and frustrated. All the affected males in the family showed characteristic abnormal behavior, in particular aggressive, and sometimes violent behavior. These males in the family displayed mild impairment of cognitive functions and some types of abnormal impulsive behavior which includes arson, attempted rape, and exhibitionism. Even attempted suicide was reported in a single case. The defect discovered was later found to be a mutation in the gene that codes for monoamine oxidase A (MAOA gene). Brunner showed that in the affected males there was a mutation in the gene for the enzyme monoamine oxidase A (MAOA). The enzyme deactivates the hormones and neurotransmitters epinephrine and norepinephrine, more commonly known as noradrenaline and adrenaline. At this time, Brunner said that an "MAO-A deficiency is associated with a recognizable behavioral phenotype that included disturbed regulation of impulsive aggression. The transmission pattern of Brunner syndrome in the families reported was consistent with X-linked recessive inheritance. A man with Brunner syndrome is what expert psychiatrists refer to as “a bad guy.”
Volkows, N. D., & Muenke, M. (2012). Human Genetics. The genetics of addiction, Vol 131(6), 773-777. Retrieved from http://dx.doi.org/10.1007/s00439-012-1173-3
Wiste, A. K., Arango, V., Ellis, S. P., Mann, J. J., & Underwood, M. D. (2008). Norepinephrine And Serotonin Imbalance In The Locus Coeruleus In Bipolar Disorder. Bipolar Disorders, 10(3), 349-359.
Graham, TE. (1998) Effects of Caffeine on Metabolism, Exercise Endurance and Catecholamine Responses and Withdrawl. London
While searching the web I found many good articles which explained how neurotransmitters affect personality. In some cases norepinepherin can encourage quick emotional responses like anger and also discourage logical thinking, while serotonin can cause irritability and a lack of rational emotion. All of them can cause anger, anxiety, depression, insecure feelings, and fear. To find out what the characteristics of personality are, I found another site appropriate. It lists 16 types of personality that are controlled by various combinations of 4 dimensions: extrovert vs. introvert, sensor vs. intuitive, thinker vs. feeler, and judger vs. perceiver. You can see how some of these could be determined by neurotransmitters.
In the brainstem, the most primitive part of the brain, lie clusters of serotonin neurons. The nerve fiber terminals of the serotonergic neurons extend all throughout the central nervous system from the cerebral cortex to the spinal cord. This neurotransmitter is responsible for controlling fundamental physiological aspects of the body. In the central nervous system (CNS), serotonin has widespread and often profound implications, including a role in sleep, appetite, memory, learning, temperature regulation, mood, sexual behavior, cardiovascular function, muscle contraction, and endocrine regulation. Not only does this bioamine control physiological aspects of the body, but it also has an involvement in behaviors like eating, sleeping and aggression. Serotonin has been noted to produce an inhibitory effect on the nervous system that calms, soothes and generates feelings of general contentment and satiation.
Personality is a term that has largely been considered an unproblematic concept and primarily refers to the varying kinds of characteristics of individuals. Despite this assumption, psychologists have constantly used the word in different ways. The varying views in the use of this concept or term are fueled by the fact that psychology usually makes generalizations regarding individuals. Generally, personality seeks to examine the many differences and similarities between individuals. Formal evaluation and study of personality have mainly focused on patterns of similarities versus patterns of differences among individuals. When evaluating patterns of differences, the concept of abnormality has emerged and attracted huge concerns among psychologists. Since the issue is controversial, there are concerns whether individual differences in personality can be effectively explained with reference to genes.
Answers on which genes affect anti-social behavior have started to emerge from genetic studies. In a study done on mice, if the MAOA gene (monoamine oxidase A), is neutralized the mice become extremely aggressive. If the gene is reactivated they return to their normal behavior. Studies on humans have also implied that the lack of the MAOA gene is responsible for anti-social behavior. The challenge now is to understand which genes affect this behavior.
Many conducted research by looking into identical twins and their personality types. Even when the twins were separated, they expressed some of the same behaviors and traits as their twin which concluded that some traits are inheritable. This thought can go deeper into the brain through a domain called personality neuroscience where people have discovered the dopamine receptor gene (Pastorino & Doyle-Portillo, pg. 479, 2015). This gene influences the amount of serotonin in the brain and can cause greater anxiety levels in these people. The founding of this gene solidifies the fact that biology and personality are indeed
Not one gene can cause Schizophrenia by itself. This illness may result from the gene that make important brain chemicals malfunctioning. This malfunctioning may affect the ...
Neurochemical factors, part of the biological profile, may also be involved in Joe’s depression symptoms. Two neurotransmitters in the brain are associated with
Bio-Psychologists study the principles of biology as it relates to the comprehension of psychology in the field neuroscience that underlies ones emotions, ideology, and actions (Brittanica). Based upon the conduction of research, the relationship between the brain and ones behavior extends to the physiological process in one’s intellect. Scientists are cognizant that neurotransmitters function as a significant role in mood regulation and other aspects of psychological problems including depression and anxiety. A biological perspective are relevant to psychology in three techniques including: the comparative method, physiology, and the investigation of inheritance (Saul Mc. Leod).
Some factors that are explored in studies involves the genetics in a person, how parents treat their children, influences peers have and the situations that a person may experience throughout their childhood and adult life. There is a possible connection between the feelings of anxiety, aggression and fear with a genetic makeup in a person’s body (Huff, 2004). Research has even shown that if an individual was abuse, whether physical or verbally they are at risk for developing a personality disorder as well (Huff, 2004). Another interesting study conducted by Robert Krueger, PhD, exploring the influences that can contribute to the development of a personality disorder, looks at studying personality traits within identical twins who did not grow up together. In the study, it appeared that genetics contributed more to a person personality trait then the environment they were in. Krueger opinion was that “The predominant reason normal and abnormal personality are linked to each other is because they are linked to the same underlying genetic mechanisms” (Huff,
In some cases the causes of mental illness primarily found inside the individual. Some of them have been associated with an abnormal balance of neurotransmitters in the brain. If they are out of balance the communication between nerve cell in the brain disrupted (Royal Australian and New Zealand College of psychiatrist, 2005). Hence, leading to symptoms of mental illness like depression, schizophrenia. On the other hand, genetics also plays a significant role to acquire mental disorder, which is passed...