Nearly 30 000 sequences were collected from public databases and used for the lineage analyses, resulting in 184 lineages. The viral gene segments showed a wide range of diversity; HA was partitioned into 78 lineages whereas MP only into seven (Table 1) . Mining the aforementioned sequences resulted in $2300 complete genomes, which consists of 156 unique genotypes with 50 serotypes (http://www.flugenome.org/show_genotypes.php). Serotypes may comprise as many as 15, different genotypes; 