Gene duplication and other evolutionary strategies: From the RNA world to the future.
Gene duplication and other evolutionary strategies: From the RNA world to the future.
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DOI：
10.1023/a:1022627311114
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发表时间：
2003-01-01
期刊：
影响因子：
--
通讯作者：
Brosius, Juergen
中科院分区：
文献类型：
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作者：
Brosius, Juergen
从假设的 RNA 世界开始，很明显，许多进化转变导致了现存物种的复杂性。遗传物质的复制根源于RNA世界。基因扩增的两条主要途径之一，即逆转录，起源于促进向 DNA 作为遗传物质转变的机制。即使在现代基因组中，逆位过程也会导致遗传新颖性，包括蛋白质和 RNA 编码基因的复制，以及调控元件及其并置。我们研究已知的进化原理是否以及在多大程度上可以应用于基于 RNA 的世界。我们得出的结论是，新达尔文主义的主要基本原理，包括扩增、变异和选择，已经支配着 RNA 和 RNP 世界的进化。在这个假想的RNA世界中，遗传物质的交换几乎没有限制，并且在后期充当边界的原则，例如魏斯曼屏障、分子生物学的中心法则或达尔文阈值不存在或处于初级阶段。 RNA 不仅仅是一个基因：它具有双重作用，通常在同一个分子中具有基因型和表型功能。核子（任何离散的核酸序列）是在个体和群体的基础上进行选择的。单个核子的表现和成功明显取决于给定细胞中其他核子的类型。在 RNA 世界中，过渡可能已经开始朝着核子连接产生复合线性 RNA 基因组的方向发展，这种排列需要 RNA 加工的起源。串联的基因组可能限制了遗传物质的无限制交换；与此同时，自私的名词更难清除。连锁基因组也可能构成了表型/基因型分离的开始。当模板化蛋白质生物合成引入 RNP 世界时，这种任务分工得到了扩展，当 DNA 取代作为遗传物质时，这种情况更是如此。上述障碍和阈值增加，水平基因转移的重要性和程度随着主要进化转变而波动。在最近的转变——我们将在有生之年目睹的快速进化转变——的黎明之际，拉马克主义的一种形式正在抬头。
Beginning with a hypothetical RNA world, it is apparent that many evolutionary transitions led to the complexity of extant species. The duplication of genetic material is rooted in the RNA world. One of two major routes of gene amplification, retroposition, originated from mechanisms that facilitated the transition to DNA as hereditary material. Even in modern genomes the process of retroposition leads to genetic novelties including the duplication of protein and RNA coding genes, as well as regulatory elements and their juxtapositon. We examine whether and to what extent known evolutionary principles can be applied to an RNA-based world. We conclude that the major basic Neo-Darwinian principles that include amplification, variation and selection already governed evolution in the RNA and RNP worlds. In this hypothetical RNA world there were few restrictions on the exchange of genetic material and principles that acted as borders at later stages, such as Weismann's Barrier, the Central Dogma of Molecular Biology, or the Darwinian Threshold were absent or rudimentary. RNA was more than a gene: it had a dual role harboring, genotypic and phenotypic capabilities, often in the same molecule. Nuons, any discrete nucleic acid sequences, were selected on an individual basis as well as in groups. The performance and success of an individual nuon was markedly dependent on the type of other nuons in a given cell. In the RNA world the transition may already have begun towards the linkage of nuons to yield a composite linear RNA genome, an arrangement necessitating the origin of RNA processing. A concatenated genome may have curbed unlimited exchange of genetic material; concomitantly, selfish nuons were more difficult to purge. A linked genome may also have constituted the beginning of the phenotype/genotype separation. This division of tasks was expanded when templated protein biosynthesis led to the RNP world, and more so when DNA took over as genetic material. The aforementioned barriers and thresholds increased and the significance and extent of horizontal gene transfer fluctuated over major evolutionary transitions. At the dawn of the most recent transformation, a fast evolutionary transition that we will be witnessing in our life times, a form of Lamarckism is raising its head.