Nasir Arshan, Sun Feng-Jie, Kim Kyung Mo, Caetano-Anollés Gustavo
Evolutionary Bioinformatics Laboratory, Department of Crop Sciences and Illinois Informatics Institute, University of Illinois, Urbana, Illinois.
Ann N Y Acad Sci. 2015 Apr;1341:61-74. doi: 10.1111/nyas.12735. Epub 2015 Mar 10.
The origin and evolution of viruses remain mysterious. Here, we focus on the distribution of viral replicons in host organisms, their morphological features, and the evolution of highly conserved protein and nucleic acid structures. The apparent inability of RNA viral replicons to infect contemporary akaryotic species suggests an early origin of RNA viruses and their subsequent loss in akaryotes. A census of virion morphotypes reveals that advanced forms were unique to viruses infecting a specific supergroup, while simpler forms were observed in viruses infecting organisms in all forms of cellular life. Results hint toward an ancient origin of viruses from an ancestral virus harboring either filamentous or spherical virions. Finally, phylogenetic trees built from protein domain and tRNA structures in thousands of genomes suggest that viruses evolved via reductive evolution from ancient cells. The analysis presents a complete account of the evolutionary history of cells and viruses and identifies viruses as crucial agents influencing cellular evolution.
病毒的起源和进化仍然是个谜。在这里，我们关注病毒复制子在宿主生物体中的分布、它们的形态特征，以及高度保守的蛋白质和核酸结构的进化。RNA病毒复制子显然无法感染当代真核生物物种，这表明RNA病毒起源较早，随后在真核生物中消失。对病毒粒子形态类型的普查表明，高级形态是感染特定超群的病毒所特有的，而在感染所有细胞生命形式生物体的病毒中观察到更简单的形态。结果暗示病毒起源于具有丝状或球形病毒粒子的祖先病毒。最后，根据数千个基因组中的蛋白质结构域和tRNA结构构建的系统发育树表明，病毒是从古代细胞通过简化进化而来的。该分析完整地呈现了细胞和病毒的进化史，并将病毒确定为影响细胞进化的关键因素。
