The NA of TX47 is an exact nucleotide match at all positions (1409) but C823T (TamiFlu Resistance) with Nanjing02, Pennsylvania10, Illinois04 and Arkansas03.
TamiFlu Resistance is indicated via 275Y on the Neuraminidase. The sequence displays the following NA Quadruple Combination:
106V, 248N, 275Y, 286S
The following permutations are now represented on the eight PF11 anti-viral resistant sequences:
106V, 248N, 275Y, 286S = WA28, WA29, TX47
106I, 248N, 275Y, 286S = Osaka180
106I, 248D, 275Y, 286S = HK2369, Yamaguchi22, Denmark528, Hunan SWL3
Until the 2009-08-21 deposit of the two Washington sequences, all 275Y TamiFlu-Resistant specimens on PF11 backgrounds were paired with 106I. Today we see 3 of 8 with 106V.
The trending toward a stronger pairing of 248N with 275Y continues as discussed in the Washington Post with a 50 / 50 split of the specimens carrying Asparagine (N) and Aspartate (D).
The Hydra Effect will be more strongly documented when the population size of the sequence database increases.
An n equal to 8 gives little to contemplate.
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