RT-PCR products for sequencing were prepared using primer
pairs: HA_1F and HA_486BR, HA _245F and HA_787R, and HA
680F and HA _1218R, available at http://msc.jcvi.org/infl_a_virus/
primers.shtml, as previously published (Salzberg et al., 2007). RTPCR
products were purified using the QIAquick PCR Purification Kit
(Qiagen). Sequencing reactions were carried out using a Big Dye
Terminator v3.1Cycle Sequencing Kit using universal M13 primers
and were run in an automatic DNA sequencer (Applied Biosystems
3130/3130x Genetic Analyzer).