Presence of rRNA-like regions in Genbank viral sequences

The keystone difference between viruses and other domains of life is an absence of own translation apparatus in viruses. However, the rapidly accumulating amount of genomic information indicates that a noticeable number of viral genomes contain sequences related to ribosomal RNA. In order to clarify the conservatism and possible evolutionary pathways of such sequences we have analyzed rRNA-like viral fragments available in NCBI GenBank. A significant number of such entries can be related to wrong assemblies and mis-annotations. However, in some cases the presence of rRNA-like sequences could be an effect of a lateral transfer of the nucleic acid from the host organism, and may reflect the ancestry of the viral evolution. Many of the found sequences are characterized with a low GC-content and their similarity may be the accidental consequence of the depletion of nucleotide composition. The analysis of seemingly correctly annotated longer sequences with a higher GC-content indicated that the origin of these sequences can be related to the events of horizontal transfer basically from modern or ancestral hosts or other members of their ecological niche. © 2021 IEEE.