Gene environment and culture interaction--论文代写范文精选

基因和环境相互作用，带来的机会扩展范围和神经科学的力量，通过引入机会合作，也是实验神经科学原因。在他们看来,解决人类精神病理学，环境因素如何影响外部的人,进入神经系统和改变它的元素生成一个无序的症状。下面的paper代写范文进行讲述。

Much recent work in American biological psychiatry has emphasized the search for gene-environment interactions. Caspi and Moffitt (2006), for example, claim that such interactions occur when the effect of exposure to an environmental pathogen on a person’s health is conditional on his or her genotype. The first evidence that genotype moderates the capacity of an environmental risk to bring about mental disorders was, according to them, reported in 2002, (Caspi et al., 2002), in a study of the role of genotype in the cycle of violence in maltreated children. 
Caspi and Moffitt (2006) claim that the gene-environment interaction approach brings opportunities for extending the range and power of neuroscience by introducing opportunities for collaboration between experimental neuroscience and research on gene-environment interactions. Successful collaboration can, in their view, solve the biggest mystery of human psychopathology: how does an environmental factor, external to the person, get inside the nervous system and alter its elements to generate the symptoms of a disordered mind? Concentrating the considerable resources of neuroscience and gene-environment interaction on this question will, they claim, bring discoveries that advance the understanding of mental disorders, and increase the potential to control and prevent them. 

One of the most cited of recent studies of gene-environment interactions is, indeed, the work of Caspi et al. (2003), who found that genetic variation in the promoter region of the serotonin transporter gene (5-HTTLPR;[OMIM182138]), in interaction with stressful life events, contributes to a predisposition to major depression. As Risch et al. (2009) put it, this result was striking and potentially paradigm shifting because numerous previous studies of this same polymorphism, without examining environmental risk factors or life events, had not consistently shown either a strong or replicated association with depression. 

A subsequent meta-analysis was conducted by Risch et al. (2009) that combined data from some 14 studies having a total of 14,250 participants, some 1769 of whom met criteria for depression. Risch et al. state that most of the participants were white, except for a multiethnic sample in one study, and an Asian sample in another. Contrary to the results of Caspi et al. (2003), they found no evidence that the serotonin transporter genotype alone, or in interaction with stressful life events, is associated with an elevated risk of depression. 

The Asian study, by J. Kim et al. (2006), involved 732 Korean community residents ages 65+, a fair number indeed. Some 88 percent at baseline did not meet criteria for depression. Kim et al., in contrast with Risch et al., in spite of using ‘standard’ instruments for both measures of depression and life events (translated into Korean), found a strong statistical trend suggesting that environmental risk of depression is indeed modified by at least two genes, and that gene-environment interactions are found even into old age. Given the scathing analyses by Arnett, Heine, and Henrich et al., the bitter conflict between the results of Caspi et al. (2003) and Risch et al. (2009) is in serious danger of becoming simply a culture-bound tempest in a distinctly American teapot.

The necessity for the inclusion of culture in the operation of fundamental psychological phenomena is emphasized by the observations of Nisbett et al. (2001), and others, following the tradition of Markus and Kitayama (1991), regarding profound differences in basic perception between test subjects of Southeast Asian and Western cultural heritage across an broad realm of experiments. East Asian perspectives are characterized as holistic and Western as analytic. Nisbett et al. (2001) find: 
(1) Social organization directs attention to some aspects of the perceptual field at the expense of others.
(2) What is attended to influences metaphysics. 
(3) Metaphysics guides tacit epistemology, that is, beliefs about the nature of the world and causality. 
(4) Epistemology dictates the development and application of some cognitive processes at the expense of others. 
(5) Social organization can directly affect the plausibility of metaphysical assumptions, such as whether causality should be regarded as residing in the field vs. in the object. 
(6) Social organization and social practice can directly influence the development and use of cognitive processes such as dialectical vs. logical ones. 

Nisbett et al. (2001) conclude that tools of thought embody a culture’s intellectual history, that tools have theories built into them, and that users accept these theories, albeit unknowingly, when they use these tools. More recently, Masuda and Nisbett (2006) examined cultural variations in change blindness, a phenomenon related to inattentional blindness, and found striking differences between Western and East Asian subjects. They presented participants with still photos and with animated vignettes having changes in 6 focal object information and contextual information. 

Compared to Americans, East Asians were more sensitive to contextual changes than to focal object changes. These results, they conclude, suggest that there can be cultural variation in what may seem to be basic perceptual processes. H. Kim et al. (2010) have extended this line of work to examine the interaction between genes and culture as determinants of individuals’ locus of attention. As the serotonin (5-HT) system has been associated with attentional focus and the ability to adapt to changes in reinforcement, they examined the serotonin 1A receptor polymorphism (5-HTR1A). Koreans and European Americans were geneotyped and reported their chronic locus of attention. They found a significant interaction between 5-HTR1A and culture in the locus of attention. Koreans reported attending to the field more than European Americans, and this cultural difference was moderated by 5-HTR1A. 

There was a linear pattern such that those homozygous for the G allele, which is associated with reduced ability to adapt to changes in reinforcement, more strongly endorsed the culturally reinforced mode of thinking than those homozygous for the C allele, with those heterozygous in the middle. Kim et al. claim that their findings suggest that the same genetic predisopsition can result in divergent psychological outcomes, depending on an individual’s cultural context. The sample used in this study included 149 Korean and 140 European subjects. Given the problems with the Caspi et al. work, it is clear that replication across larger samples will be needed. That being said, the results of H. Kim et al. do indeed underline the necessity of expanding work on psychiatric disorders to gene-culture-environment interactions. It seems likely, however, that, overall, culture-environment interaction effects will predominate. Nonetheless, the effects of genetic structure on that interaction might well provide important insights as to etiology and possible treatment.(paper代写)

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