Background & Aims: There is a serious disagreement between researchers about the genetic basis of crime. Some biologists and clinical criminologists deny the existence of a chromosome or a crime gene. Some forensic psychiatrists believe that certain alleles of genes are directly or indirectly involved in the commission of violent acts. Some consider co-perpetration to be a crime, personal psychological characteristics such as emotional intelligence. In this regard, not understanding the feelings and emotions of others and proper control of their emotions in problematic situations and failure in positive management about others, may lead to deviant behaviors such as abuse of others and crime. Among the environmental factors, the effect of "diet" and nutrition on criminal behaviors has been done by examining the relationship between alcohol, drugs, and sugar with such behaviors. Environmental pollution also affects the incidence of crime. For example, many industrial products have significantly increased environmental pollution, the toxic substances of which such as lead, mercury, and pesticides enter the human body through various methods, which are severely disrupted. Perceptual and behavioral related. About violent crime, four types of neurotransmitters have been studied more than others: serotonin, norepinephrine, and epinephrine dopamine (monoamines). Numerous studies of low serotonin replacement rates in people with a history of violent behavior.Including those who have committed fires and other violent crimes, and those who commit suicide violently. Studies of people who have been released from prison have also revealed of serotonin replacement rates. The lower they were, the more likely they were to commit violent crimes. It has been suggested that dysfunction of the central serotonin pathways is involved in the underlying mechanisms of suicidal, antisocial, and criminal behaviors. Norepinephrine and epinephrine also increase blood pressure. High blood pressure can lead to severe heart and brain problems, and because the disease has an internal and individual aspect, the person who commits the crime due to diabetes and high blood pressure and heart and brain problems is not aware of his problem and usually. He does not cite his illness to defend himself.
In criminology, genes influence criminal behavior in two ways: first, by transmitting biological traits, which are discussed under the heading of "inheritance and crime." Second, through the changes that may occur in them that can be examined under "genetic disorders", one of the most important cases is disorders such as XXY or YYX.
Biological markers are the most important and practical marker systems that have a wide range and are developing and evolving every day. Because they are at the first level of gene expression, they are very accurate and have high diversity and high polymorphisms.
To examine the genetic aspects of a crime, the technique of determining the genetic structure is a process in which differences in a person's genetic makeup are determined by examining a person's DNA sequence by comparing it to another personal sequence or a reference sequence.
The present study aimed to determine the relationship between the relative frequency of certain alleles of the gene responsible for transporting serotonin and a history of violent crime.
Methods: Perpetrators of violent crimes In this study, by the available sampling method, 50 people were selected from among the thieves of violent behaviors, including bags and mobile phones. None of the participants had a history of schizophrenia and/or antisocial personality disorder, aggression, child trauma, child abuse, or various types of abuse (based on diagnostic criteria (DSM-IV TR). Explain the scope and method of study to all participants. Was given, and informed and written informed consent was obtained from them.
Two common functional polymorphisms (STin2) are VNTR-17 and 5HTTLPR in the promoter and the second intron. The transporter gene (SCL6A4) 5 is known. The former contains 16 (long; L) or 14 (short; S) repeats of 22 bases, while the latter contains 12 (long) or 10 (short) repeats of 17 bases. After venous blood sampling, DNA was extracted from venous blood. Using appropriate primers, the 5HTTLPR, and VNTR-17 (STin2) polymorphisms in the 5HTT gene were examined by AFLP analysis.
Results: For the 5HTTLPR gene, the highest frequency belonged to the SS SS allele. Regarding the VNTR-17 gene (STin2), the highest frequency for the allele was 12.10. In the next position, 12.12, and finally 10.10 was the lowest relative frequency (24%). Therefore, the order of frequency of 5HTTLPR gene alleles in perpetrators of violent crimes is as follows: SS> SL> LL. The order of frequency of (STin2) VNTR-17 gene alleles in perpetrators of violent crimes is as follows: 10/12>12/12>10/10.
Conclusion: The gene for the serotonin transporter protein, which plays an important role in regulating the intensity and duration of serotonergic signaling at synapses, has long been suggested as the gene responsible for various psychiatric disorders. Previous studies have shown that gene polymorphism The transporter serotonin, 5HTTLPR (genetic polymorphism), may be associated with aggressive and antisocial behavior. The human HTT 5 gene (SLC6A4) contains a replicating element consisting of 22 bp (5 HTTLPR) that inserts/removes 44 bp, resulting in "long" and "short" types (16 and 12 bp, respectively) (14). Due to the existence of multiple control groups in previous studies that have a reference (as a group that has not committed a crime of violence) and due to the limitations of this study, if we compare the many ratios in the samples of this study with control groups of previous studies, it will become clear that a similar pattern In other words, the order of the proportions of allele frequencies in violent offenders is not different from that of normal individuals (15). However, this means that the above ratios in this study are consistent with similar offenders in other studies, for example in a study in prisons. In Siberia, Russia, the LL allele had the highest frequency and the SS allele had the lowest frequency. Although the pattern of relative abundance of gene alleles responsible for serotonin transporter production in the present study is very similar to the gene pattern of individuals with mental disorders leading to violent criminal behaviors, a causal relationship between the frequency of specific alleles of this gene and the occurrence of such behaviors cannot be deduced.