Running Head: Utility of Gene Vectors 1
Utility of Gene Vectors
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Abstract
The extent to which hereditary genes play a role in addiction is under question. This paper provides insight into the arguments for gene therapy and the reasons some sections of thinkers are not convinced.
Introduction
There is a global menace of addiction from substances as seemingly mild as painkillers and caffeine to hard drugs such as cocaine and LSD. In the bid to understand the biology addiction, scientists are questioning reasons why some families have a higher likelihood of addiction as compared to others in the same locality. The subject of why some people grow addicted while others do not after experimentation is also under scrutiny.
Scientists are now conducting extensive studies into the effects of genes on addiction if any through genetic mapping. Genetic mapping is the attempt to isolate the specific gene that causes some tendencies, drug abuse in this case. How true the statement that genetics causes drug addiction is a topic under debate.
Literature Review
Every human life function is dictated by the composition of the body’s functional proteins. It is these proteins that have the task to produce enzymes that will dictate the body’s response to various chemical substances. The composition of these body proteins is in turn dictated by Deoxyribonucleic acid (DNA). This is a unique template which the body cells utilize to generate proteins. Part of this DNA sequence is inherited explaining why related people share common traits. The studies and books quoted from below utilize this concept.
In 1995, Sander and company concluded a study on the effects of the genes dopamine factors D1, D2, and D3 genes. In their sample population of 278 alcoholics, they found positive evidence of the allele DRD3 gene in alcoholics. The presence of the DRD3 gene increased the chances of addicts to have delirium in the sample. These results resulted in increased interest and with it funding from the National Institute on Drug Abuse into studies in this area.
Gorwood and his peers (2012) compiled research data and came to the conclusion that genes involved in the dopaminergic system are directly linked to susceptibility to drug abuse. The dopamine system includes the dopamine receptors, their transporting agents, and dopamine metabolic enzymes. They narrowed down their phenotypes to their disposition to seek novelty, how inhibited their behavior is, how impulsive their decision making is, and their reaction to stress. Their research showed that the relation of hereditary genes to these characteristics was substantial.
Chen and five other scientists in the year 2014 sought to find out if genes are involved in the ease with which some people stop smoking nicotine. They utilized a placebo-controlled approach on 709 candidates on rehabilitation trials. Two nicotinic receptors are targeted, Alpha 5 subunit and Cytochrome P450 2A6. These two genotypes were suspected to influence a patient’s response to rehabilitation drugs.
They found that people with the allele, Cytochrome P450 2A6, were most likely to respond well to replacement treatments (Chen et al. 2014). They also found that bupropion, a chemical associated with relapse, was ineffective in Cytochrome P450 2A6.
Derringer and company (2012) realized that the use of entire genome studies to explain variations almost always failed. They used another approach, selective scoring. In this method, the gene changes that had been previously shown to affect the dopamine system were concurrently examined and given weights for cocaine dependence symptoms.
They yielded results that showed that 273 SNPs in the eight alleles related to the dopaminergic system. This means that cocaine dependence susceptibility too is associated with these set of dopaminergic genes.
The amount of research on drugs is not limited to human beings genetics. There are a lot of influential results in animal research as well (Genetic Science Learning Center, 2013). Mice with the allele Mpdz shows a lower incidence of severe withdrawal from barbiturates. Cannabinoid receptor proteins (Cnr l) in mice result in little morphine intake. Htr l B genes in mice have been shown to cause a higher cocaine and alcohol attraction compared to mice lacking this gene variation (Genetic Science Learning Center, 2013).
The Genetic Science Learning Center (2013) describes studies in which genetically modified mice were stripped off the Subunit Beta 2, of the nicotinic cholinergic gene. These mice were showed to have a lower addiction to cocaine as a result of their reduced reward pathway. The neuropeptide Y in mice has demonstrated to be influential in the preference of alcohol. On the other hand, mice with the improper sequencing of the gene Per 2 are tolerant to three times as much alcohol as their counter parts (Genetic Science Learning Center, 2013).
Addiction and Genetics have also been extended to the insect kingdom. Tests in fruit flies that have the inability to synthesize the enzyme, tyramine remain sedate regardless of the number of cocaine doses they are given (Genetic Science Learning Center, 2013).
The two main reasons that solidify the argument for the genetic influence for drug abuse are outlined below.
There is irrefutable evidence from multiple independent sources, some of which have been outlined above, as to the effect of genes on drug intake and ease of withdrawal.
Drug abuse problems have been observed to run in families. It has been observed that there is between 40% to 60% (Genetic Science Learning Center, 2013) chance of the child of an alcoholic parent to be alcoholic too.
Discussion
A section of influential thinkers who have been involved with drug rehabilitation are of the view that the environment is the greatest influence on substance abuse. Studies on the hereditability of drug addiction are very likely to be completely misinterpreted. Families are most likely to live in the same environment and to be exposed to the same conditions (stimuli). Therefore, the susceptibility of people to drug dependence may not be easily differentiated to be as a result of the environment or genetics.
Additionally, substance abuse is majorly a personal choice people make. Apart from highly addictive drugs like LSD, people continually make the deliberate choice to use drugs multiple times before addiction sets in. The psychology of individuals is greater than their biology when it comes to the personal choices that they make.
Conclusions
Most people will experiment with drugs at one point in their lives, and some of them will be addicted while others will not. The environment dictates the likelihood of experimentation with drugs, the period in which it will last, and the push for cessation. Genetics, on the other hand, explains why some people will become addicts after experimentation while others will not.
References
i. Gorwood, P., Le Strat, Y., Ramoz, N., Dubertret, C., Moalic, J. M., & Simonneau, M. (2012). Genetics of dopamine receptors and drug addiction. Human genetics, 131(6), 803-822.
ii. Chen, L. S., Bloom, A. J., Baker, T. B., Smith, S. S., Piper, M. E., Martinez, M., … & Bierut, L. (2014). Pharmacotherapy effects on smoking cessation vary with nicotine metabolism gene (CYP2A6). Addiction, 109(1), 128-137.
iii. Derringer, J., Krueger, R. F., Dick, D. M., Aliev, F., Grucza, R. A., Saccone, S., … & Kramer, J. R. (2012). The aggregate effect of dopamine genes on dependence symptoms among cocaine users: cross-validation of a candidate system scoring approach. Behavior genetics, 42(4), 626-635.
iv. Genetic Science Learning Center. (2013, August 30) Genes and Addiction. Retrieved October 20, 2016, from http://learn.genetics.utah.edu/content/addiction/genes/
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Utility of Gene Vectors
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Utility of Gene Vectors
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Running Head: Utility of Gene Vectors 1
Utility of Gene Vectors
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