[摘要]：Hao (2011) reported that the PB2 genes of three swine influenza A viruses were likely generated through homologous recombination between two closely related parental strains. However, we show that Hao's observation is an artifact of incorrect taxon sampling arising through the lack of an appropriate evolutionary context. Through rigorous phylogenetic analyses we explain the evolutionary origins of these stains and confirm the lack of any statistical support for intra-segmental recombination. (C) 2011 Elsevier B.V. All rights reserved.
