Genetic Diversity and Distribution of Human Norovirus in China (1999–2011)
Phylogenetic analysis of GII.4 NoV sequences from China. Two rooted phylogenetic trees were reconstructed using partial ORF1 (1029 nt) (a) and ORF2 (811 nt) (b) nucleotide sequences. GII.1 (JN797508) and GII.20 (AB542917) were used as the outgroups in (a) and (b), respectively. The trees were generated using the maximum-likelihood method. Bootstrap values above 70%, estimated with 1000 pseudoreplicate data sets, are indicated at each node. The distance scale represents the number of nucleotide substitutions per position. The variant clusters are highlighted, and the NoV GII.4 sequences from China are indicated with a diamond. The reference sequences were retrieved from the NCBI database. The subtree of the Den Haag 2006b cluster in (b) includes 47 representative sequences.