Masters Degrees (Genetics)
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Browsing Masters Degrees (Genetics) by Subject "Aggression"
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Item Open Access Aspects of the genetics of human aggressive behaviour(University of the Free State, 2016-02-11) Odendaal, Zurika; Spies, J. J.; Spies, P.English: Abstract indicated in Script chapter by chapterItem Open Access Aspects of the genetics of human aggressive behaviour(University of the Free State, 2012-12) Odendaal, Zurika; Spies, J. J.; Spies, P.Item Open Access The association of specific polymorphisms in the serotonergic system with aggressive, impulsive and suicidal behaviour(University of the Free State, 2016-06) Louw, Susan; Spies, J. J.; Heathfield, L. J.; Schneider, S. R.English: Suicidal behaviour and the consequences thereof are a major global issue and need to be researched in order to promote a better understanding of this maladaptive behaviour. However, understanding the aetiology of suicidal behaviour is important, but difficult, as it is multifactorial and complex. Although there is a growing body of research pertaining to suicidal behaviour, there is a lack of research on the genetic contribution towards an endophenotype for suicidal behaviour in South Africa. Due to the complex nature of suicidal behaviour, it was suggested that the use of an endophenotype would contribute to the possible intervention in this maladaptive behaviour. It has been suggested that some people were genetically predisposed to suicidal behaviour, and more importantly, the tendency to act on suicidal thoughts, and that this genetic vulnerability, underlain by the serotonergic system, might possibly be linked to inherited personality traits such as impulsiveness and aggression. Impulsiveness and aggression have therefore been suggested as possible endophenotypes of suicidal behaviour. Variation in the chosen genetic markers of the serotonergic system may modify the endophenotype of impulsivity and aggression, and in turn, influence the phenotype, suicidal behaviour. The aim of the research was to determine if impulsivity and aggression can act as a potential endophenotype for suicidal behaviour, and therefore, firstly, to determine whether aggression and impulsivity, as personal variables, are associated with suicidal behaviour, and secondly, to investigate the possible association of candidate polymorphisms (HTR1A rs6295, HTR1B rs6296, HTR2A rs6311 and SLC6A4 HTTLPR) of the serotonergic system to impulsivity, aggression and attempted suicide. Genes can thus be studied as a contributing factor and not the only factor that influence suicidal behaviour. A cohort of 25 research participants with a previous suicide attempt were recruited and matched to 25 healthy controls. All participants completed the BIS-11, RPQ, and BPAQ as quantifiable measures. Participants were also genotyped for HTR1A (rs6295), HTR1B (rs6296), HTR2A (rs6311) and SLC6A4 HTTLPR. The results for this study indicated that the suicide attempters scored significantly higher than the control group in all the questionnaires for aggression and impulsivity. This led to the conclusion that impulsivity and aggression is positively associated with suicidal behaviour. However, with regards to the molecular genetic analysis, only the HTR2A gene variant, rs6311, showed a significant difference between the suicide attempters and controls, with the A allele being more frequent in the suicide attempters (p = 0.0066). The suicide attempters were the only group that presented with the X allele for SLC6A4 HTTLPR and further studies are needed to replicate this finding. Interesting trends were observed regarding the other genetic variants, but no significant results were obtained. For HTR1A rs6295, the homozygous GG genotype conferred the highest risk for impulsive and aggressive behaviours in suicide attempters. The G allele for HTR2A rs6311, together with the S allele for HTTLPR, also seemed to increase impulsive and aggressive traits. In the case of HTTLPR, this finding was valid irrespective of the presence of suicidal behaviour. Overall, the results provide support for the use of behavioural measures of impulsivity and aggression as an endophenotype for suicidal behaviour. Some support was also found for the use of impulsive aggression as a single construct with regards to suicidal behaviour. The combination of psychology and genetic results are among the first ever reported for suicide attempters in South Africa. Despite the limited size of the study, perhaps due to the sensitivity of the construct under investigation, this study nevertheless adds significant value to the body of research pertaining to the under-studied topic of suicidal behaviour in South Africa. This study can improve phenotyping that will ultimately benefit South-African individuals.Item Open Access The role of emotional intelligence and a functional polymorphism in the MAO-A gene on aggression in humans(University of the Free State, 2012-05) Laubscher, Nadia; Spies, J. J.Article 1: Aggression is a complex trait, with both genetic and environmental factors important in its aetiology. It is a universal problem, for which better solutions are needed. This study will focus mainly on the influence of genetic and environmental factors on two subtypes of aggression, namely reactive- and proactive aggression. The moderate heritability values of these subtypes make them ideal candidates for such a study. The genetic components of aggression include the upper-limit heritability estimates for the subtypes by means of correlations between first-degree relatives. Thereafter the role of variants of one specific gene, the MAO-A gene will be examined. The role of emotional intelligence as a specific environmental factor influencing aggression is discussed. Very few studies have been done on the possible influence of emotional intelligence on aggression. Traumatic event exposure will also be studied as a possible secondary influencing factor. Since self-report measures are used, the effect of social desirability bias will be determined. In this chapter each of the variables under study is briefly described, followed by the most salient motivations why these specific variables were seen as the most suitable for this investigation. In addition, the specific aims of the dissertation are briefly outlined. Article 2: Aggression is a highly prevalent and costly problem in societies throughout the world. Treatment options are available, but needs to be improved or adjusted to really be able to curb the problem of aggression. The paper aims to highlight key points in the aggression literature in order to improve researchers’ understanding of the construct of aggression and possible causes underlying aggression, as well as factors that may exacerbate aggression. Therefore, this paper reviews the literature on aggression in humans, and covers aspects relating to the defini-tion of aggression, the various subtypes of aggression, evidence for variable en-vironmental and heritable influences on aggression, as well as looking at specific genes and hormones influencing aggression. Specifically, the influence on ag-gression of the monoamine oxidase A enzyme, the gene that encodes it (MAO-A), and the neurotransmitters that it metabolizes (serotonin and norepinephrine) are looked at. In addition, emotional intelligence as a possible influencing factor on the occurrence of aggression is also covered. This is done to provide a start-ing point for research aiming to develop treatments for aggression, whether they are psychotherapeutic programmes aimed at improving emotional intelligence or psychopharmaceutic drugs aimed at the genetic and hormonal mechanisms un-derlying aggression.