Figure 2S. Pyrograms showing sequence data at residue E119 of the NA gene of received isolates (IRs) of A/Texas/12/2007 (H3N2). A reverse primer

(HuN2NA-119-R377-seq), in Table 1, was used for sequencing the region containing the 119 residue, hence the sequences displayed on the pyrograms are reverse complements to the original sequence. Isolates received prior to June 9th 2007 (A-F) exhibited the sequence TTC, complementary to GAA which encodes the wild type amino acid, glutamic acid (E119). Isolates received on and after June 9th (G-I, L and M) exhibited the sequence TAC, complementary to GTA which codes for valine (E119V), with the exception of isolates received June 25 th, July 2nd and August 14th (J, K and N) which exhibited the wildtype sequence (E119).

A Sample #2 (Collected March 11th 2007/Passage X1) Result: AGGTTCTCTT GTCACCCAGA TGTCCC (Wild type sequence TTC complementary to GAA which encodes glutamic acid, E119) A GG TT C T C TT G T C A CCCA G A T G T CCC

130

120

110

E S C A T G C A T G C A T G C A T G C A T G C A T G C A T G C A G T C A T G C A T G C A T G C A T G C A T G C A T G C A T G 5 10 15 20 25 30 35 40 45 50 55 60

B Sample #4 (Collected March 25th 2007/Passage X1) Result: AGGTTCTCTT GTCACCCAGA TGTCCC (Wild type sequence TTC complementary to GAA which encodes glutamic acid)

130 A GG TT C T C TT G T C A CCCA G A T G T CCC 125

120

115

110

105 E S C A T G C A T G C A T G C A T G C A T G C A T G C A T G C A G T C A T G C A T G C A T G C A T G C A T G C A T G C A T G 5 10 15 20 25 30 35 40 45 50 55 60 C Sample #6 (Collected May 23rd 2007/Passage X1) Result: AGGTTCTCTT GTCACCCAGA TGTCCC (Wild type sequence TTC complementary to GAA which encodes glutamic acid)

130 A GG TT C T C TT G T C A CCCA G A T G T CCC 125

120

115

110

105 E S C A T G C A T G C A T G C A T G C A T G C A T G C A T G C A G T C A T G C A T G C A T G C A T G C A T G C A T G C A T G 5 10 15 20 25 30 35 40 45 50 55 60

D Sample #8 (Collected May 28th 2007/Passage X1) Result: AGGTTCTCTT GTCACCCAGA TGTCCC (Wild type sequence TTC complementary to GAA which encodes glutamic acid) A GG TT C T C TT G T C A CCCA G A T G T CCC 125

120

115

110

105 E S C A T G C A T G C A T G C A T G C A T G C A T G C A T G C A G T C A T G C A T G C A T G C A T G C A T G C A T G C A T G 5 10 15 20 25 30 35 40 45 50 55 60

E Sample #11 (Collected May 31st 2007/Passage X1) Result: AGGTTCTCTT GTCACCCAGA TGTCCC (Wild type sequence TTC complementary to GAA which encodes glutamic acid, E119)

130 A GG TT C T C TT G T C A CCCA G A T G T CCC

120

110

E S C A T G C A T G C A T G C A T G C A T G C A T G C A T G C A G T C A T G C A T G C A T G C A T G C A T G C A T G C A T G 5 10 15 20 25 30 35 40 45 50 55 60 F Sample #13 (Collected June 6th 2007/Passage X1) Result: AGGTTCTCTT GTCACCCAGA TGTCCC (Wild type sequence TTC complementary to GAA which encodes glutamic acid, E119)

125 A GG TT C T C TT G T C A CCCA G A T G T CCC

120

115

110

105 E S C A T G C A T G C A T G C A T G C A T G C A T G C A T G C A G T C A T G C A T G C A T G C A T G C A T G C A T G C A T G 5 10 15 20 25 30 35 40 45 50 55 60

G Sample #14 (Collected June 9th 2007/Passage X) Result: AGGTACTCTT GTCACCCAGA TGTCCC (Mutant sequence TAC complementary to GTA which encodes valine, E119V)

A GG T A C T C TT G T C A CCCAG A T G T CCC 120

115

110

105 E S C A T G C A T G C A T G C A T G C A T G C A T G C A T G C A G T C A T G C A T G C A T G C A T G C A T G C A T G C A T G 5 10 15 20 25 30 35 40 45 50 55 60

H Sample #18 (Collected June 9th 2007/Passage X1) Result: AGGTACTCTT GTCACCCAGA TGTCCC (Mutant sequence TAC complementary to GTA which encodes valine, E119V)

140 A GG T A C T C TT G T C A CCCAG A T G T CCC

130

120

110

E S C A T G C A T G C A T G C A T G C A T G C A T G C A T G C A G T C A T G C A T G C A T G C A T G C A T G C A T G C A T G 5 10 15 20 25 30 35 40 45 50 55 60 I Sample #20 (Collected June 11th 2007/Passage X) Result: AGGTACTCTT GTCACCCAGA TGTCCC Mutant sequence TAC complementary to GTA which encodes valine, E119V)

A GG T A C T C TT G T C A CCCAG A T G T CCC 125

120

115

110

105 E S C A T G C A T G C A T G C A T G C A T G C A T G C A T G C A G T C A T G C A T G C A T G C A T G C A T G C A T G C A T G 5 10 15 20 25 30 35 40 45 50 55 60

J Sample #23 (Collected June 25th 2007/Passage X1) Result: AGGTTCTCTT GTCACCCAGA TGTCCC (Wild type sequence TTC complementary to GAA which encodes glutamic acid, E119) A GG TT C T C TT G T C A CCCA G A T G T CCC 130

120

110

E S C A T G C A T G C A T G C A T G C A T G C A T G C A T G C A G T C A T G C A T G C A T G C A T G C A T G C A T G C A T G 5 10 15 20 25 30 35 40 45 50 55 60

K Sample #25 (Collected July 2nd 2007/Passage X1) Result: AGGTTCTCTT GTCACCCAGA TGTCCC (Wild type sequence TTC complementary to GAA which encodes glutamic acid, E119)

125 A GG TT C T C TT G T C A CCCA G A T G T CCC

120

115

110

105 E S C A T G C A T G C A T G C A T G C A T G C A T G C A T G C A G T C A T G C A T G C A T G C A T G C A T G C A T G C A T G 5 10 15 20 25 30 35 40 45 50 55 60 L Sample #27 (Collected July 9th 2007/Passage X1) Result: AGGTACTCTT GTCACCCAGA TGTCCC (Mutant sequence TAC complementary to GTA which encodes valine, E119V)

140 A GG T A C T C TT G T C A CCCAG A T G T CCC

130

120

110

E S C A T G C A T G C A T G C A T G C A T G C A T G C A T G C A G T C A T G C A T G C A T G C A T G C A T G C A T G C A T G 5 10 15 20 25 30 35 40 45 50 55 60

M Sample #30 (Collected July 23rd 2007/Passage X1) Result: AGGTACTCTT TCCACCAAGT CCC Mutant sequence TAC complementary to GTA which encodes valine, E119V)

A GG T A C T C TT G T C A CCCAG A T G T CCC 125

120

115

110

105 E S C A T G C A T G C A T G C A T G C A T G C A T G C A T G C A G T C A T G C A T G C A T G C A T G C A T G C A T G C A T G 5 10 15 20 25 30 35 40 45 50 55 60

N Sample #33 (Collected August 14th 2007//Passage X1) Result: AGGTTCTCTT GTCACCCAGA TGTCCC (Wild type sequence TTC complementary, to GAA which encodes glutamic acid, E119)

125 A GG TT C T C TT G T C A CCCA G A T G T CCC 120

115

110

105 E S C A T G C A T G C A T G C A T G C A T G C A T G C A T G C A G T C A T G C A T G C A T G C A T G C A T G C A T G C A T G 5 10 15 20 25 30 35 40 45 50 55 60