 Such dual functionality is uncommon among the currently existing sugar-manipulating enzymes, and possibly suggests the ancient nature of the PBCV-1 GMD.Infection cycle studies in PBCV-1 revealed that the virus relies on a unique capsid glycosylation process independent of the host's ER or Golgi machinery.This feature has not yet been observed in any other virus currently known to science and potentially represents an ancient and conserved pathway, which could have evolved before eukaryogenesis, which was estimated to occur around 2.0-2.7 billion years ago.