42-7 and 30-2 are recessive mutants. Parental, 30-2 or 42-7 cells were labeled with the membrane dyes Oregon Green or Vybrant DID that mark cells green and blue respectively. The cells were then mixed (either as self-self or as parental and mutant combinations) and fused with polyethelene glycol (PEG). The fused cells were infected with HIV-1 virus transducing DsRed and analyzed by flourecence cyometry. The bar graph illustrates the percentage of fused cells expressing DsRed and line graphs the geometic mean intensity of DsRed expression.