TABLE 1.

PCR primers used for preparation of Southern blot probes

Primer	Sequence	Position on vRNA
PB1 forward	5′-ATGGATGTCAATCCGACCTTACTTTTCTTA-3′	25→54
PB1 backward	5′-CGTTTCAATACACGAGTTTTC-3′	354←334
PB2 forward	5′-ATGGAAAGAATAAAAGAACTAAGAAATCTA-3′	28→57
PB2 backward	5′-TATTTGTTATTGGTCCATTCC-3′	349←329
PA forward	5′-ATGGAAGATTTTGTGCGACAATGCTTCAAT-3′	25→54
PA backward	5′-CCCTGTAGTGTTGCAAATACT-3′	321←301