First Identification of Human Adenovirus Subtype 21a in China With MinION and Illumina Sequencers

Ye, Fuqiang; Han, Yifang; Zhu, Juanjuan; Li, Peng; Zhang, Qi; Lin, Yanfeng; Wang, Taiwu; Lv, Heng; Wang, Changjun; Wang, Chunhui; Zhang, Jinhai

We detected a recombinant event approximately starting from position 33,260 in the present HAdV21a genome that indicated a recombinant E4 gene originating from the HAdV3 prototype (Figure 5) . BLASTN analysis revealed an identity of 99.54% between E4 genes from the current isolate and the HAdV3 prototype, which decreased to a range of 93.85-98.88% when it was aligned to E4 region from other non-HAdV3 members. A phylogenetic tree constructed based on the E4 gene sequences also revealed that all the strains in subtype 21a clustered with HAdV3 (Supplementary Figure S6) . BLASTN identities of all available HAdV21a E4 genes against the HAdV3 E4 gene ranged from 99.42 to 99.57%, which were higher than those of HAdV21p against HAdV3 (98.64%). Thus, the recombinant E4 region in HAdV21a strains should be a common feature that has never been reported before.