Mayer Christian
Institute of Physical Chemistry, CENIDE, University of Duisburg-Essen, 45141 Essen, Germany.
Life (Basel). 2023 Feb 21;13(3):603. doi: 10.3390/life13030603.
The basic idea of the RNA world as an early step towards life relies on a molecular evolution process based on self-replicating RNA strands. It is probably the oldest and most convincing model for efficient prebiotic evolution. Obviously, the functionality of RNA sequences depends on order (i.e., the definition of their sequence) as well as on complexity (i.e., the length of their sequence). Order and complexity seem to be crucial parameters in the course of RNA evolution. In the following, an attempt is made to define these parameters and to identify characteristic mechanisms of their development. Using a general RNA world scenario including the free monomer units, the sequential order is defined based on statistical thermodynamics. The complexity, on the other hand, is determined by the size of a minimal algorithm fully describing the system. Under these conditions, a diagonal line in an order/complexity-diagram represents the progress of molecular evolution. Elementary steps such as repeated random polymerization and selection follow characteristic pathways and finally add up to a state of high system functionality. Furthermore, the model yields a thermodynamic perspective on molecular evolution, as the development of a defined polymer sequence has a distinct influence on the entropy of the overall system.
RNA世界作为生命起源早期阶段的基本理念，依赖于基于自我复制RNA链的分子进化过程。它可能是高效的前生物进化中最古老且最具说服力的模型。显然，RNA序列的功能取决于顺序（即其序列的定义）以及复杂性（即其序列的长度）。顺序和复杂性似乎是RNA进化过程中的关键参数。接下来，我们尝试定义这些参数，并识别其发展的特征机制。使用包括游离单体单元的一般RNA世界场景，基于统计热力学定义顺序。另一方面，复杂性由完全描述系统的最小算法的大小决定。在这些条件下，顺序/复杂性图中的对角线代表分子进化的进程。诸如重复随机聚合和选择等基本步骤遵循特征路径，最终累积成高系统功能状态。此外，该模型从热力学角度看待分子进化，因为特定聚合物序列的发展对整个系统的熵有显著影响。
