Noble Denis
Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK.
Interface Focus. 2017 Oct 6;7(5):20160159. doi: 10.1098/rsfs.2016.0159. Epub 2017 Aug 18.
Stochasticity is harnessed by organisms to generate functionality. Randomness does not, therefore, necessarily imply lack of function or 'blind chance' at higher levels. In this respect, biology must resemble physics in generating order from disorder. This fact is contrary to Schrödinger's idea of biology generating phenotypic order from level order, which inspired the central dogma of molecular biology. The order originates at higher levels, which constrain the components at lower levels. We now know that this includes the genome, which is controlled by patterns of transcription factors and various epigenetic and reorganization mechanisms. These processes can occur in response to environmental stress, so that the genome becomes 'a highly sensitive organ of the cell' (McClintock). Organisms have evolved to be able to cope with many variations at the molecular level. Organisms also make use of physical processes in evolution and development when it is possible to arrive at functional development without the necessity to store all information in DNA sequences. This view of development and evolution differs radically from that of neo-Darwinism with its emphasis on blind chance as the origin of variation. Blind chance is necessary, but the origin of functional variation is not at the molecular level. These observations derive from and reinforce the principle of biological relativity, which holds that there is no privileged level of causation. They also have important implications for medical science.
生物体利用随机性来产生功能性。因此，随机性并不一定意味着在更高层次上缺乏功能或“盲目偶然”。在这方面，生物学在从无序中产生有序方面必定与物理学相似。这一事实与薛定谔关于生物学从层次有序中产生表型有序的观点相反，后者启发了分子生物学的中心法则。这种有序起源于更高层次，它会限制较低层次的组成部分。我们现在知道这包括基因组，它受转录因子模式以及各种表观遗传和重组机制的控制。这些过程可以因环境压力而发生，从而使基因组成为“细胞的一个高度敏感器官”（麦克林托克）。生物体已经进化到能够应对分子水平上的许多变异。在有可能实现功能性发育而无需将所有信息存储在DNA序列中的情况下，生物体在进化和发育过程中也会利用物理过程。这种发育和进化观点与新达尔文主义截然不同，新达尔文主义强调盲目偶然是变异的起源。盲目偶然是必要的，但功能性变异的起源并不在分子水平。这些观察结果源于并强化了生物学相对性原理，该原理认为不存在特权因果层次。它们对医学科学也具有重要意义。
