Origins and Evolution of the Global RNA Virome

Yuri I. Wolf; Darius Kazlauskas; Jaime Iranzo; Adriana LucÍa-Sanz; Jens H. Kuhn; Mart Krupovic; Valerian V. Dolja; Eugene V. Koonin

While the present study was in preparation, a major attempt on a comprehensive virus 802 classification has been published (121). This work analyzed a dendrogram that was produced 803 from distance matrices between viruses derived from sequence similarity scores combined with 804 measures of gene composition similarity. . Unlike our present analysis, this approach pre-805 supposes monophyly of each of the Baltimore classes. Furthermore, given that their analysis is 806 based on measures of similarity rather than on phylogenetic analysis proper, this approach is best 807 regarded as producing a phenetic classification of viruses rather that an evolutionary 808 reconstruction as such. Some of the groups delineated by this method, particularly, among +RNA 809 viruses, are closely similar to those reported here. Others, however, are widely different: for 810 instance, the order Mononegavirales does not come across as monophyletic in their 811 dendrograms. We did not attempt a complete comparison; such an exercise could be useful in the 812 future, for better understanding the routes of RNA virus evolution. 813