  As the infection of 2019-nCoV coronavirus is quickly developing into a global
pneumonia epidemic, careful analysis of its transmission and cellular
mechanisms is sorely needed. In this report, we re-analyzed the computational
approaches and findings presented in two recent manuscripts by Ji et al.
(https://doi.org/10.1002/jmv.25682) and by Pradhan et al.
(https://doi.org/10.1101/2020.01.30.927871), which concluded that snakes are
the intermediate hosts of 2019-nCoV and that the 2019-nCoV spike protein
insertions shared a unique similarity to HIV-1. Results from our
re-implementation of the analyses, built on larger-scale datasets using
state-of-the-art bioinformatics methods and databases, do not support the
conclusions proposed by these manuscripts. Based on our analyses and existing
data of coronaviruses, we concluded that the intermediate hosts of 2019-nCoV
are more likely to be mammals and birds than snakes, and that the "novel
insertions" observed in the spike protein are naturally evolved from bat
coronaviruses.
