Koonin Eugene V, Krupovic Mart, Dolja Valerian V
National Center for Biotechnology Information, National Library of Medicine, Bethesda, Maryland, USA.
Institut Pasteur, Université Paris Cité, CNRS UMR6047, Archaeal Virology Unit, Paris, France.
Environ Microbiol. 2023 Jan;25(1):40-44. doi: 10.1111/1462-2920.16207. Epub 2022 Sep 29.
Viruses are considered to be the most abundant biological entities on earth. They also display striking genetic diversity as emphatically demonstrated by the recent advances of metagenomics and metatranscriptomics. But what are the limits of this diversity, that is, how many virus species in the earth virome? By combining the available estimates of the number of prokaryote species with those of the virome size, we obtain back-of-the-envelope estimates of the total number of distinct virus species, which come out astronomically large, from about 10 to about 10 . The route of virus origins apparently involved non-viral replicators capturing and exapting various cellular proteins to become virus capsid subunits. How many times in the history of life has this happened? In other words, how many realms of viruses, the highest rank taxa that are supposed to be monophyletic, comprise the global virome? We argue that viruses emerged on a number (even if far from astronomical) independent occasions, so the number of realms will considerably increase from the current 6, by splitting some of the current realms, giving the realm status to some of the currently unclassified groups of viruses and discovery of new distinct groups.
病毒被认为是地球上数量最为丰富的生物实体。正如宏基因组学和宏转录组学的最新进展所显著表明的那样，它们还展现出惊人的遗传多样性。但是这种多样性的极限是什么，也就是说，地球病毒组中有多少种病毒呢？通过将原核生物物种数量的现有估计值与病毒组大小的估计值相结合，我们得到了不同病毒物种总数的粗略估计，其数量大得惊人，约为10的多少次方到10的多少次方。病毒起源的途径显然涉及非病毒复制因子捕获并改造各种细胞蛋白，使其成为病毒衣壳亚基。在生命史上这种情况发生了多少次？换句话说，构成全球病毒组的病毒界（被认为是单系的最高分类单元）有多少个？我们认为病毒是在若干（即使远非天文数字）独立的情况下出现的，因此病毒界的数量将从目前的6个大幅增加，途径包括拆分一些现有的病毒界、将一些目前未分类的病毒群体赋予界的地位以及发现新的不同病毒群体。
