Phylogenetic rooted tree based on partial nucleotide sequences (≈812 pb.) of the hemagglutinin (HA) gene from low pathogenic Avian Influenza H5N2 viruses isolated between 2002 and 2008. Reverse transcriptase PCR was used for the amplification of the HA cleavage site sequence of different Avian Influenza viruses isolated in Mexico. Maximum parsimony and best heuristic tree search analysis showing the relationships of nucleotide sequences of HA genes. Similar tree topologies were obtained by the maximum likelihood method. Tree was rooted using the nucleotide sequence from the vaccine strain (AY497063). Numbers on branches indicate bootstrap values after 1,000 replicates. Scale bar indicates the number of changes over the whole sequence. Low pathogenic Avian Influenza H5N2 viruses isolated in Mexico between 1994-1996 (light-blue circles), 1997-1998 (dark-blue circles), 2002-2006 (orange circles) and 2007-2008 (red circles).