The Modes of Evolutionary Emergence of Primal and Late Pandemic Influenza Virus Strains from Viral Reservoir in Animals: An Interdisciplinary Analysis

Table 6

Genes contributed by avian genomes to pandemic influenza strains (based on various data presented above).

Pandemic strain	Avian genes contributed	Contemporary porcine input
1918—H1N1	PA PB1	Yes
1957—H2N2	PB1 HA NA	None
1968—H3N2	PB1 HA	None
2009—H1N1	PA PB2	Yes