Department of Biosciences, University of Helsinki, , POB 64, Gustaf Hälströmin katu 2, 00560 Helsinki, Finland.
J R Soc Interface. 2014 Feb 19;11(94):20131017. doi: 10.1098/rsif.2013.1017. Print 2014 May 6.
The sequencing of the human genome raises two intriguing questions: why has the prediction of the inheritance of common diseases from the presence of abnormal alleles proved so unrewarding in most cases and how can some 25 000 genes generate such a rich complexity evident in the human phenotype? It is proposed that light can be shed on these questions by viewing evolution and organisms as natural processes contingent on the second law of thermodynamics, equivalent to the principle of least action in its original form. Consequently, natural selection acts on variation in any mechanism that consumes energy from the environment rather than on genetic variation. According to this tenet cellular phenotype, represented by a minimum free energy attractor state comprising active gene products, has a causal role in giving rise, by a self-similar process of cell-to-cell interaction, to morphology and functionality in organisms, which, in turn, by a self-similar process entailing Darwin's proportional numbers are influencing their ecosystems. Thus, genes are merely a means of specifying polypeptides: those that serve free energy consumption in a given surroundings contribute to cellular phenotype as determined by the phenotype. In such natural processes, everything depends on everything else, and phenotypes are emergent properties of their systems.
为什么在大多数情况下,从异常等位基因的存在预测常见疾病的遗传证明是如此无益,以及如何由大约 25000 个基因产生如此丰富的复杂性,这在人类表型中显而易见?有人提出,通过将进化和生物体视为依赖于热力学第二定律的自然过程,可以为这些问题提供一些启示,这与最初形式的最小作用原理等效。因此,自然选择作用于任何从环境中消耗能量的机制上的变异,而不是作用于遗传变异上。根据这一原则,细胞表型由包含活性基因产物的最小自由能吸引子状态表示,通过细胞间相互作用的自相似过程,在生物体中产生形态和功能,生物体通过一个涉及达尔文比例数的自相似过程,对其生态系统产生影响。因此,基因只是指定多肽的一种手段:那些在特定环境中有助于消耗自由能的基因,作为由表型决定的细胞表型的一部分发挥作用。在这种自然过程中,一切都取决于其他一切,而表型是其系统的涌现特性。