Metabolites are small molecules involved in cellular metabolism where they act as reaction substrates or products. The term ‘metabolomics’ refers to the comprehensive study of these molecules. The concentrations of metabolites in biological tissues are under genetic control, but this is limited by environmental factors such as diet. In adult mono- and dizygotic twin pairs, we estimated the contribution of genetic and shared environmental influences on metabolite levels by structural equation modeling and tested whether the familial resemblance for metabolite levels is mainly explained by genetic or by environmental factors that are shared by family members. Metabolites were measured across three platforms: two based on proton nuclear magnetic resonance techniques and one employing mass spectrometry. These three platforms comprised 237 single metabolic traits of several chemical classes. For the three platforms, metabolites were assessed in 1407, 1037 and 1116 twin pairs, respectively. We carried out power calculations to establish what percentage of shared environmental variance could be detected given these sample sizes. Our study did not find evidence for a systematic contribution of shared environment, defined as the influence of growing up together in the same household, on metabolites assessed in adulthood. Significant heritability was observed for nearly all 237 metabolites; significant contribution of the shared environment was limited to 6 metabolites. The top quartile of the heritability distribution was populated by 5 of the 11 investigated chemical classes. In this quartile, metabolites of the class lipoprotein were significantly overrepresented, whereas metabolites of classes glycerophospholipids and glycerolipids were significantly underrepresented.

代谢物是参与细胞代谢的小分子，在其中它们充当反应底物或产物。术语“代谢组学”是指对这些分子的全面研究。生物组织中代谢物的浓度处于遗传控制之下，但这受到诸如饮食等环境因素的限制。在成年单卵双生子和双卵双生子对中，我们通过结构方程模型估算了遗传和共享环境影响对代谢产物水平的贡献，并测试了代谢产物水平的家族相似性主要是由遗传因素还是由家庭成员共有的环境因素来解释的。在三个平台上测量了代谢产物：两个基于质子核磁共振技术，一个使用质谱。这三个平台包括几种化学类别的237个单一代谢特征。对于这三个平台，分别在1407、1037和1116对双胞胎中评估了代谢产物。我们进行了功效计算，以确定在这些样本量下可以检测到多少百分比的共享环境变化。我们的研究没有发现证据表明共享环境对成年后评估的代谢产物有系统性贡献，共享环境定义为在同一家庭中共同成长。几乎所有237种代谢物均观察到显着的遗传力。共享环境的重要贡献仅限于6种代谢物。遗传力分布的最高四分位数由11种调查的化学类别中的5种组成。在这个四分位数中