Fig. 1

A model for selective incorporation of IAV genome. Different vRNAs are shown as lines of varied colors (red, green, yellow, blue, black, purple, cyan, and brown), and homologous gene segments from different viruses are shown as different shapes. Nucleotides with low-NP-binding may form secondary structures which are necessary for the incorporation of vRNP. The favored hypothesis of the highly selective genome packaging mechanism relies on the redundant and plastic network of RNA-RNA and potentially RNA-nucleoprotein interactions. Homologous gene segments of IAV compete for incorporation into virions and segment containing matched packaging sequences relative to the background of the virus is packaged preferentially