Fisher Simon E
Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, OX3 7BN, UK.
Cognition. 2006 Sep;101(2):270-97. doi: 10.1016/j.cognition.2006.04.004. Epub 2006 Jun 9.
The rise of molecular genetics is having a pervasive influence in a wide variety of fields, including research into neurodevelopmental disorders like dyslexia, speech and language impairments, and autism. There are many studies underway which are attempting to determine the roles of genetic factors in the aetiology of these disorders. Beyond the obvious implications for diagnosis, treatment and understanding, success in these efforts promises to shed light on the links between genes and aspects of cognition and behaviour. However, the deceptive simplicity of finding correlations between genetic and phenotypic variation has led to a common misconception that there exist straightforward linear relationships between specific genes and particular behavioural and/or cognitive outputs. The problem is exacerbated by the adoption of an abstract view of the nature of the gene, without consideration of molecular, developmental or ontogenetic frameworks. To illustrate the limitations of this perspective, I select two cases from recent research into the genetic underpinnings of neurodevelopmental disorders. First, I discuss the proposal that dyslexia can be dissected into distinct components specified by different genes. Second, I review the story of the FOXP2 gene and its role in human speech and language. In both cases, adoption of an abstract concept of the gene can lead to erroneous conclusions, which are incompatible with current knowledge of molecular and developmental systems. Genes do not specify behaviours or cognitive processes; they make regulatory factors, signalling molecules, receptors, enzymes, and so on, that interact in highly complex networks, modulated by environmental influences, in order to build and maintain the brain. I propose that it is necessary for us to fully embrace the complexity of biological systems, if we are ever to untangle the webs that link genes to cognition.
分子遗传学的兴起正在广泛影响各个领域，包括对诵读困难、言语和语言障碍以及自闭症等神经发育障碍的研究。目前有许多研究正在试图确定遗传因素在这些疾病病因中的作用。除了对诊断、治疗和理解有明显影响外，这些研究的成功有望揭示基因与认知和行为方面之间的联系。然而，在寻找遗传和表型变异之间的相关性时，表面上的简单性导致了一种常见的误解，即特定基因与特定行为和/或认知输出之间存在直接的线性关系。由于采用了对基因本质的抽象观点，而没有考虑分子、发育或个体发生框架，这个问题变得更加严重。为了说明这种观点的局限性，我从最近对神经发育障碍遗传基础的研究中选取了两个案例。首先，我讨论将诵读困难分解为由不同基因指定的不同成分的提议。其次，我回顾FOXP2基因的故事及其在人类言语和语言中的作用。在这两个案例中，采用基因的抽象概念都可能导致错误的结论，这些结论与当前分子和发育系统的知识不相容。基因并不指定行为或认知过程；它们产生调节因子、信号分子、受体、酶等等，这些在高度复杂的网络中相互作用，并受到环境影响的调节，以构建和维持大脑。我认为，如果我们想要理清将基因与认知联系起来的网络，就必须充分接受生物系统的复杂性。
