Szabó Péter, Scheuring István, Czárán Tamás, Szathmáry Eörs
Department of Plant Taxonomy and Ecology, Research Group of Ecology and Theoretical Biology, Eötvös University, 1/c Pázmány P. sétány, H-1117 Budapest, Hungary.
Nature. 2002 Nov 21;420(6913):340-3. doi: 10.1038/nature01187.
The emergence of functional replicases, acting quickly and with high accuracy, was crucial to the origin of life. Although where the first RNA molecules came from is still unknown, it is nevertheless assumed that catalytic RNA enzymes (ribozymes) with replicase function emerged at some early stage of evolution. The fidelity of copying is especially important because the mutation load limits the length of replicating templates that can be maintained by natural selection. An increase in template length is disadvantageous for a fixed digit copying fidelity, however, longer molecules are expected to be better replicases. An iteration for longer molecules with better replicase function has been suggested and analysed mathematically. Here we show that more efficient replicases can spread, provided they are adsorbed to a prebiotic mineral surface. A cellular automaton simulation reveals that copying fidelity, replicase speed and template efficiency all increase with evolution, despite the presence of molecular parasites, essentially because of reciprocal atruism ('within-species mutualism') on the surface, thus making a gradual improvement of replicase function more plausible.
功能复制酶的出现，其作用迅速且准确性高，对生命起源至关重要。尽管首个RNA分子的来源尚不清楚，但人们仍然认为具有复制酶功能的催化RNA酶（核酶）在进化的某个早期阶段出现。复制的保真度尤为重要，因为突变负荷限制了可通过自然选择维持的复制模板的长度。对于固定的数字复制保真度而言，模板长度的增加是不利的，然而，更长的分子有望成为更好的复制酶。有人提出并对具有更好复制酶功能的更长分子进行了数学分析。在这里，我们表明，更高效的复制酶能够传播，前提是它们吸附在益生元矿物表面。细胞自动机模拟显示，尽管存在分子寄生虫，但复制保真度、复制酶速度和模板效率都会随着进化而提高，这主要是由于表面上的互惠利他行为（“种内共生”），从而使复制酶功能的逐步改善更具合理性。
