[Genetic recombination between natural isolates of influenza virus serotypes H1N1 and H3N2]

Oligonucleotide mapping of individual genes was used for search of possible genetic recombinants between natural isolates of influenza H1N1 and H3N2 viruses isolated in the USSR in 1977-1979. No antigenic hybrids and recombinants with the antigenic structure H3N2 were found, however, it was shown that isolates of H1N1 viruses of 1979 (the A/USSR/61/79 strain) might represent genetic recombinants carrying genes P1 + P2 from H3N2 viruses, the M-gene of the USSR/61/79 virus being closest in its structure to the analogous gene of the earliest isolate of H3N2 viruses, namely A/Hong Kong/1/68. Possible selective advantages of virus recombinants having M-genes from viruses of a different serotype are discussed.