What Does "the RNA World" Mean to "the Origin of Life"?
What Does "the RNA World" Mean to "the Origin of Life"?
复制标题
DOI：
10.3390/life7040049
复制
发表时间：
2017-11-29
期刊：
影响因子：
--
通讯作者：
Ma W
中科院分区：
文献类型：
--
作者：
Ma W
与生命的两个不同方面：达尔文进化论和自我维持相对应，生命的起源也应该分为两个问题：达尔文进化论的起源和自我维持的产生。因为我们所关心的生命的“自我维持”应该是由其遗传信息所“定义”的相关系统的自我维持，所以这种自我维持不可能在达尔文进化论起源之前出现，而达尔文进化论的起源正是以遗传信息的出现为标志的。RNA世界概念背后的逻辑并不像人们所认为的那样站得住脚。也就是说，遗传分子和功能分子，即使不是同一种物质，也可能在一开始就一起出现并启动了进化--只要遗传分子可以“简单地”编码功能分子。然而，由于这些或那些原因，替代方案通常比RNA世界更不令人信服。特别是，当考虑到支持RNA世界从头起源的实验证据越来越多时，现在似乎有理由相信这样一个世界可能刚刚出现在地球生命的最初阶段。因此，我们获得了一个具体的场景，我们试图欣赏这些基本问题，涉及生命的起源。根据这个场景中可能出现的场景，达尔文进化论可能起源于分子水平，在功能性RNA上实现。当两个或更多的功能RNA出现时，为了它们的有效合作，应该有一个原始细胞出现的选择压力。但直到出现了“单一原始细胞”，它的所有RNA基因都连接到一条染色体上，达尔文进化才向细胞水平迈出了完整的一步--不再受到分子水平低级进化的严重限制。在原始细胞出现之前，自我维持没有意义。选择压力有利于探索越来越多的基本原材料，导致生命的进化趋势变得越来越自我维持。各实体适应环境的新职能，包括参与自我维持本身的职能，将给自我维持带来新的负担-这些职能的优势必须超过相应的劣势。
Corresponding to life’s two distinct aspects: Darwinian evolution and self-sustainment, the origin of life should also split into two issues: the origin of Darwinian evolution and the arising of self-sustainment. Because the “self-sustainment” we concern about life should be the self-sustainment of a relevant system that is “defined” by its genetic information, the self-sustainment could not have arisen before the origin of Darwinian evolution, which was just marked by the emergence of genetic information. The logic behind the idea of the RNA world is not as tenable as it has been believed. That is, genetic molecules and functional molecules, even though not being the same material, could have emerged together in the beginning and launched the evolution—provided that the genetic molecules can “simply” code the functional molecules. However, due to these or those reasons, alternative scenarios are generally much less convincing than the RNA world. In particular, when considering the accumulating experimental evidence that is supporting a de novo origin of the RNA world, it seems now quite reasonable to believe that such a world may have just stood at the very beginning of life on the Earth. Therewith, we acquire a concrete scenario for our attempts to appreciate those fundamental issues that are involved in the origin of life. In the light of those possible scenes included in this scenario, Darwinian evolution may have originated at the molecular level, realized upon a functional RNA. When two or more functional RNAs emerged, for their efficient cooperation, there should have been a selective pressure for the emergence of protocells. But it was not until the appearance of the “unitary-protocell”, which had all of its RNA genes linked into a chromosome, that Darwinian evolution made its full step towards the cellular level—no longer severely constrained by the low-grade evolution at the molecular level. Self-sustainment did not make sense before protocells emerged. The selection pressure that was favoring the exploration of more and more fundamental raw materials resulted in an evolutionary tendency of life to become more and more self-sustained. New functions for the entities to adapt to environments, including those that are involved in the self-sustainment per se, would bring new burdens to the self-sustainment—the advantage of these functions must overweigh the corresponding disadvantage.
登录
查看更多内容
影响因子：
5.6
作者：
CRICK, FHC
通讯作者：
CRICK, FHC
影响因子：
21.8
作者：
Aumiller, William M., Jr.;Keating, Christine D.
通讯作者：
Keating, Christine D.
影响因子：
16.6
作者：
Attwater, James;Wochner, Aniela;Holliger, Philipp
通讯作者：
Holliger, Philipp
DOI：
10.3390/life5010294
发表时间：
2015-01-23
期刊：
Life (Basel, Switzerland)
影响因子：
--
作者：
Carter CW
通讯作者：
Carter CW
影响因子：
64.8
作者：
ACEVEDO, OL;ORGEL, LE
通讯作者：
ORGEL, LE