The genomic recombination events may reveal the evolution of coronavirus and the origination of 2019-nCoV

To trace the evolution of coronavirus and reveal the possible origination of the novel pneumonia coronavirus (2019-nCoV), we collected and thoroughly analyzed 2966 publicly available coronavirus genomes, including 182 2019-nCoVs strains. We observed 3 independent recombination events with statistical significance between some isolates from bats and pangolins. In consistence with previous records, we also detected the putative recombination between Bat-CoV-RaTG13 and Pangolin-CoV-2019 covering the receptor bind domain (RBD) of the spike glycoprotein (S protein), which may lead to the origination of 2019-nCoV. Population genetic analyses give estimations indicating that the recombinant region around RBD is possibly undergoing directional evolution. This may result to the adaption of the virus to be infectious in hosts. Not surprisingly, we find that the S protein of coronavirus keeps high diversity among bat isolates, which may provide a genetic pool for the origination of 2019-nCoV.