Overview Recombination exchange of genes between 2 chromosomes crossing over occurs in homologous regions Reassortment viruses with segmented genomes exchange segments analagous to high-frequency recombination results in influenza pandemics Complementation 2 viruses infect a cell, but one is mutated and has a non-functional protein the nonmutated virus helps the mutant by making protein for both viruses Phenotypic mixing 2 viruses infect a cell virus A has its own genetic material, but the surface proteins of virus B progeny viruses contain coat components and genetic material from virus A this is because they only had the genetic material from virus A genetic material is not altered pseudovirion formation when a virus's coat is entirely from another virus nucleic acid and coat are completely mismatched