We know from twin and family studies that our personality is to a large degree – probably around 40 per cent – inherited. Geneticists are busy trying to find the specific gene variants involved, but because each one on its own only exerts a modest influence, this is challenging research requiring huge samples. A new study in Nature Genetics has made a significant contribution, using the technique of Genome Wide Analysis to look for genetic variants that correlate with personality. The researchers led by Min-Tzu Lo at the University of California, San Diego have identified variations in six genetic loci that correlate with different personality trait scores, five of which were previously unknown. In a separate analysis, the researchers also showed that many of the genetic variants involved in personality overlap with those involved in the risk of developing mental health disorders.
我们从双胞胎和家庭研究中了解到,我们的人格在很大程度上——大概40%左右——来自于遗传。遗传学家正忙于寻找相关的特定基因变异,但由于每一个基因本身只起到了适度的影响,所以这一挑战性的研究需要大量样本。一项新的自然遗传学的研究作出了重大贡献,这项研究利用全基因组分析技术寻找与人格相关的基因变异。由圣地亚哥加利福尼亚大学Min Tzu Lo带领的研究人员已经确定了六个与不同人格特质相关的基因位点的变异,其中五个是以前未知的。在另一项分析中,研究人员还发现,许多与人格有关的基因变异,也和精神健康障碍的发生有关。
The researchers analysed the genomes of hundreds of thousands of people, including clients of 23andMe – a commercial service that promises to inform customers about their ancestry and health based on their DNA (usefully for present purposes, the company also asks its clients to complete personality questionnaires). Among the genetic loci the researchers identified as being linked with personality, the most influential correlated with Neuroticism scores and was on a region of chromosome 8 (specifically 8p23.1) that is known to be involved in nervous system development and developmental neuropsychiatric disorders. Another that was linked with extraversion scores was on a region of chromosome 12 (specifically 12q23.3) that has also been highlighted in genetic research into bipolar disorder.
研究人员分析了成千上万人的基因组,包括23andme(23andme是一家基因鉴定公司)的客户——这项商业服务承诺,根据客户的DNA为其提供他们祖先和健康的信息(对当前的研究目标是非常有用的,该公司还要求客户完成人格问卷)。研究人员发现,遗传位点与人格有关,与神经质得分呈正相关的最有影响力的位于8号染色体(特别是8p23.1)一个区域的基因,被认为与神经系统的发育和发育神经精神障碍有关。另一个与外倾性相关的位于12号染色(特别是12q23.3)一个区域的基因,在双相情感障碍遗传研究中显得很突出。
The researchers also compared the gene/personality correlations in their massive data sets with similar records previously obtained by the Psychiatric Genetics Consortium to look for genetic influences on mental health disorders. This showed substantial genetic correlations between personality and psychiatric disorders – that is, many of the genetic influences on personality are also implicated in the risk of developing various mental health disorders. This makes sense given what we already know about the influence of personality on mental health – for instance, high scorers on Neuroticism are at increased risk of anxiety and depression, while high scorers on Extraversion and Openness to Experience are more likely than others to be diagnosed with bipolar disorder.
在他们的大量数据中,研究人员比较了与基因/个性的相关的记录,这些数据与精神遗传协会之前获得的相关数据相似于,以寻找遗传因素对心理健康障碍的影响。这表明人格与精神疾病之间存在着大量稳定的遗传相关性——也就是说,许多对人格的遗传影响也与各种心理健康障碍的发展风险有关。正如我们已经知道的,人格对精神健康有影响,这是有道理的——例如,神经质得分高的人会增加焦虑和抑郁的风险,而外倾性和开放性得分高的人,与其他人相比,更可能被诊断为双相情感障碍。
The genetic findings largely matched this picture. For instance, in terms of shared genetic influences, the trait of Openness to Experience, bipolar disorder and schizophrenia tended to cluster together, as did Neuroticism and Depression, and Extraversion and ADHD.
遗传结果在很大程度上符合这张图片。例如,在共同的遗传影响方面,开放性的经验,双相情感障碍和精神分裂症的特质往往聚集在一起,神经质和抑郁,外向性和ADHD也是如此。
Another test the researchers were able to do was to see what proportion of the variation in the participants’ personality traits could be traced to differences in their genome – in other words to estimate the genetic heritability for each of the Big Five traits. Based on an analysis of over one million genetic variants (single-nucleotide polymorphisms; SNPs) present in the 59,000+ clients of 23andMe, the researchers found that Extraversion was the most strongly heritable trait with 18 per cent of variation in this trait traceable to differences in the genome (the estimates for Agreeableness, Conscientiousness, Neuroticism and Openness were 8 per cent, 9 per cent, 11 per cent and 10 per cent, respectively). As expected, these heritability estimates for personality are lower than those found in twin and family studies – among the reasons for this is the fact the researchers were only able to look at a fraction of the genetic variants that may play a role in personality, and were unable to explore ways that genes interact with the environment.