doi:10.1093/ve/veab038engDudas, GytisHuber, GregWilkinson, MichaelYllanes, DavidPolymorphism of genetic ambigramsART-2021-143301Double synonyms in the genetic code can be used as a tool to test competing hypotheses regarding ambigrammatic narnavirus genomes. Applying the analysis to recent observations of Culex narnavirus 1 and Zhejiang mosquito virus 3 ambigrammatic viruses indicates that the open reading frame on the complementary strand of the segment coding for RNA-dependent RNA polymerase does not code for a functional protein. Culex narnavirus 1 has been shown to possess a second segment, also ambigrammatic, termed ‘Robin’. We find a comparable segment for Zhejiang mosquito virus 3, a moderately diverged relative of Culex narnavirus 1. Our analysis of Robin polymorphisms suggests that its reverse open reading frame also does not code for a functional protein. We make a hypothesis about its role.2021http://zaguan.unizar.es/record/16590810.1093/ve/veab038http://zaguan.unizar.es/record/165908oai:zaguan.unizar.es:165908Virus evolution 7, 1 (2021), veab038 [11 pp.]byhttps://creativecommons.org/licenses/by/4.0/deed.esinfo:eu-repo/semantics/openAccess