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To identify intergenotype recombination among GII.4 variants, the NoV GII.4 variant and GII.2 genotype complete genome sequences were analyzed using the Recombination Detection Program (RDP) v.4.55 and the SimPlot program. In the 2015-2016 season, the 16 polymerase emerged in November 2015, causing 60% of all GII.4 outbreaks in the USA. KX907727), was detected in Atlanta City, USA, in 2016. The other NoV GII.4 variant, CA3477 strain (GenBank No. LC175468) was detected in the diarrheal feces of 9 patients in an outbreak in Kawasaki City, Japan, in 2016. In this study, the recombination and phylogenetic analyses showed that the Sydney 2012 variants, Kawasaki194 and CA3477, were recombinant NoV strains with a GII.4 capsid and a GII.2 polymerase gene. However, there are few reports about the role of intergenotype recombination in the emergence of the GII.4 variant in the complete genome. Previous studies show that intragenotype recombination contributed to the emergence of the recent pandemic GII.4 variant in New Orleans in 2009, and a newly identified GII.4 variant, termed Sydney 2012. Intragenotype recombination is widespread within the pandemic NoV GII.4 lineage. Recombination occurs in many RNA viruses, and can be of major evolutionary significance. The dominant global genotype that causes outbreaks and sporadic cases of gastroenteritis is genogroup II, genotype 4 (GII.4). Twenty-seven and 22 genotypes of RdRp and VP1, respectively, have been established in GII. GII is detected more frequently in clinical samples, based on the nucleotide sequence of RdRp (in ORF1) and VP1 (in ORF2). Currently, NoVs are classified into 6 major groups, genogroup I (GI) to genogroup VI (GVI), based on amino acid sequence diversities of the VP1. The norovirus (NoV), a member of the Caliciviridae family, is the leading cause of acute viral gastroenteritis, and is estimated to be the cause of almost half of all cases of gastroenteritis globally.