These viruses, which include SARS-CoV and MERS-CoV, are capable of replicating in multiple hosts, typically clusters of species. Other coronaviruses with an even broader host range possess mutations in the S glycoprotein gene that render them (a) capable of recognizing receptor orthologs, (b) “preprogrammed” to fuse a variety of host cell proteins (Graham and Baric, 2010), or (c) easily mutatable, in the course of cell culture, to recognize heparin sulfate as a receptor for docking and entry to host cells, which vastly extends their host range (de Haan et al., 2005)