Rhiza Labs FluTracker Forum

http://www.virologyj.com/content/pdf/17 ... -8-183.pdf

25 pages - full text

Positive Selection on Hemagglutinin and Neuraminidase Genes of H1N1
Influenza Viruses
Virology Journal 2011, 8:183 doi:10.1186/1743-422X-8-183

snippet:

found strong diversifying (positive) selection at HA1 156 and 190. The residues 190 and 225 are
critical determinants of the receptor-binding specificity of A/H1N1 HA, with human
viruses favouring D190/D225, swine viruses favouring D190/G225 and avian viruses
favouring E190/G225 (D190 means that the amino acid at position 190 is D, aspartic
acid.