On the stability of sequences inserted into viral genomes

Willemsen, Anouk; Zwart, Mark P

The Nanoviridae family includes ssDNA viruses with a multipartite genome that are composed of six to eight circular segments. Segmented ssDNA viruses present unique challenges when thinking about the stability of inserted sequences, because the frequency of genomic segments is highly plastic for some of these viruses. These viruses might therefore downregulate segments for expression of the inserted sequence, even if downregulation of co-localized homologous genes is costly. A lower frequency would also entail a lower mutational supply, limiting evolvability, the capacity of the virus to generate beneficial variation and subsequently adapt. Segmented viruses might therefore display rapid adaptive responses to inserted sequences, whilst simultaneously limiting their potential for longer-term evolution. To the best of our knowledge, this potentially interesting tradeoff has not been shown.