协同连接破坏序列对称性并稳定早期分子复制
Cooperative ligation breaks sequence symmetry and stabilizes early molecular replication
摘要：
每个生物都携带着复杂的DNA序列，决定了它们独特的特征和功能。一般认为，生命起源于由核苷酸的益生元聚合产生的随机寡核苷酸序列库。最初促使第一个物种的功能编码序列从这样一个随机序列库中出现的机制仍然未知。这是生命起源的核心问题。一个有趣的选择是通过自发对称性破缺的自选择机制。特定序列基序的初始浓度波动将被放大并胜过丰度较低的序列，从而增强复制和选择功能序列的信噪比。在这里，我们证明了与实验和理论研究结果，模板连接将提供这样的自我选择。在模板化连接中，当第三互补链序列使两个相邻的单链链紧密接近时，它们化学连接。一旦链达到形成双链物质的长度，这种简单的机制可能是益生元聚合化学的副产物。如这里所示，连接通过匹配序列的协同连接产生非线性复制过程，所述匹配序列自我促进其自身的延伸。这导致了增强的模板结合和更快的连接反应的级联。一个要求是通过热循环重新排列链，例如通过微尺度对流实现。假设模板连接是由产生寡核苷酸的益生元聚合的相同化学机制驱动的，该机制可以作为聚合和自稳定复制之间缺失的环节，为生命起源的达尔文进化的自主出现提供了一条途径。
英文摘要：
Each living species carries a complex DNA sequence that determines their unique features and functionalities. It is generally assumed that life started from a random pool of oligonucleotides sequences, generated by a prebiotic polymerization of nucleotides. The mechanism that initially facilitated the emergence of sequences that code for the function of the first species from such a random pool of sequences remains unknown. It is a central problem of the origin of life. An interesting option would be a self-selection mechanism by spontaneous symmetry breaking. Initial concentration fluctuations of specific sequence motifs would have been amplified and outcompeted less abundant sequences, enhancing the signal to noise to replicate and select functional sequences. Here, we demonstrate with experimental and theoretical findings that templated ligation would provide such a self-selection. In templated ligation, two adjacent single sequences strands are chemically joined when a third complementary strand sequence brought them in close proximity. This simple mechanism was a likely side-product of a prebiotic polymerization chemistry once the strands reach the length to form double stranded species. As shown here, the ligation gave rise to a nonlinear replication process by the cooperative ligation of matching sequences which self-promoted their own elongation. This led to a cascade of enhanced template binding and faster ligation reactions. A requirement was the reshuffling of the strands by thermal cycling, enabled for example by microscale convection. Assuming that templated ligation was driven by the same chemical mechanism that generated prebiotic polymerization of oligonucleotides, the mechanism could function as a missing link between polymerization and the self-stabilized replication, offering a pathway to the autonomous emergence of Darwinian evolution for the origin of life.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
