Novel Immunoglobulin Domain Proteins Provide Insights into Evolution and Pathogenesis Mechanisms of SARS-Related Coronaviruses

Yongjun Tan; Theresa Schneider; Matthew Leong; L Aravind; Dapeng Zhang

However, the remaining part of ORF1 of SARS-CoV-2 and RatG13 show no specific relationship to these 134 viruses. This suggests a recombination event between the common ancestor of SARS-CoV-2 and RaTG13, 135 and probably another member of the SARS-related clade close to CoVZXC21 and CoVZXC45. In addition 136 to this major recombination event, we identified several smaller regions which might have undergone 137 recombinational diversification during the emergence of the SARS-CoV-2 genome ( Figure S1 ). Notably, 138 many of them are clustered in three regions displaying extensive diversification, corresponding to the N-139 terminal region of the ORF1a polyprotein, the Spike protein, and the uncharacterized protein encoded 140 by ORF8 (Figure 1 and Figure S1 ). 141 142