Table 1.: Gene segment distribution in the genomes of reassortants generated from various influenza A and B viruses circulating in different years.

Influenza A Viruses
Gene Segments Before 20001 After 20002
% (n) % (n) % (n) % (n)
WT MDV WT MDV
PB2 2,1% (2) 97,9% (95) 9,6% (5) 90,4% (47)
PB1 5,2% (5) 94,8% (92) 40,4% (21) 59,6% (31)
PA 2,1% (2) 97,9% (95) 9,6% (5) 90,4% (47)
HA 100,0% (97) 0,0% (0) 100,0% (52) 0,0% (0)
NP 29,9% (29) 70,1% (68) 44,2% (23) 55,8% (29)
NA 91,8% (89) 8,2% (8) 13,5% (7) 86,5% (45)
M 42,3% (41) 57,7% (56) 65,4% (34) 34,6% (18)
NS 47,4% (46) 52,6% (51) 80,8% (42) 19,2% (10)
Influenza B Viruses
Gene Segments Before 20003 After 20004
% (n) % (n) % (n) % (n)
WT MDV WT MDV
PB2 8,3% (1) 91,7% (11) 19,9% (48) 80,1% (193)
PB1 17,0% (2) 83,0% (10) 39,8% (96) 60,2% (145)
PA 16,7% (2) 83,3% (10) 10,0% (24) 90,0% (217)
HA 100,0% (12) 0,0% (0) 100,0% (241) 0,0% (0)
NP 41,7% (5) 58,3% (7) 39,8% (96) 60,2% (145)
NA 91,7% (11) 8,3% (1) 11,2% (27) 88,8% (214)
M 50,0% (6) 50,0% (6) 90,0% (217) 10,0% (24)
NS 66,7% (8) 33,3% (4) 78,0% (188) 22,0% (53)

Influenza A viruses:1Reassortants of A/Leningrad/134/17/57 (H2N2) master donor virus (MDV) with A/Nanchang/933/95 (H3N2), A/Beijing/262/95 (H1N1), A/Perth/13/95 (H1N1), A/Johannesburg/82/96 (H1N1), A/Panama/2007/99 (H3N2), A/New Caledonia/20/99 (H1N1)2Reassortants of A/Leningrad/134/17/57 (H2N2) MDV with A/Wellington/01/04 (H3N2), A/Malaysia/01/04 (H3N2), and A/Brisbane/10/07 (H3N2).Influenza B viruses:3Reassortants of B/USSR/60/69 MDV with B/Harbin/07/94, B/Shandong/7/974Reassortants of B/USSR/60/69 MDV with B/Florida/4/06, B/Brisbane/3/07, B/Bangladesh/1994/10, and B/Wisconsin/1/10