Forterre Patrick, Prangishvili David
Institut de Génétique et Microbiologie, Université Paris-Sud, CNRS UMR 8621, 91405 Orsay Cedex, France.
Res Microbiol. 2009 Sep;160(7):466-72. doi: 10.1016/j.resmic.2009.07.008. Epub 2009 Jul 30.
Viruses are parasitic organisms that live in infected cells and produce virions to disseminate their genes. Most viral proteins have no homologues in modern cells, in contradiction with the traditional view of viruses as pickpockets of cellular genes. This suggests that viral genes essentially originated in the virosphere during replication of viral genomes and/or were recruited from cellular lineages now extinct. Some specific viral proteins are present in viruses infecting members of the three domains of Life, suggesting that viruses are indeed very ancient. In particular, structural analyses of capsid proteins have revealed that at least two types of virions originated independently before the LUCA (the Last Universal Cellular Ancestor). Although several hypotheses have been recently proposed to explain the origin of viruses, the emergence of virions, as a specific mechanism for gene dissemination, remains unexplained.
病毒是寄生生物，它们生活在受感染的细胞中，并产生病毒粒子来传播其基因。与传统上将病毒视为细胞基因窃贼的观点相反，大多数病毒蛋白在现代细胞中没有同源物。这表明病毒基因本质上起源于病毒基因组复制期间的病毒圈，和/或从现已灭绝的细胞谱系中招募而来。一些特定的病毒蛋白存在于感染生命三域成员的病毒中，这表明病毒确实非常古老。特别是，衣壳蛋白的结构分析表明，至少有两种类型的病毒粒子在最后的共同祖先（LUCA）之前就独立起源了。尽管最近提出了几种假说来解释病毒的起源，但病毒粒子作为一种特定的基因传播机制的出现仍然无法解释。
