RT Journal Article SR Electronic T1 Emergence of SARS-CoV-2 through recombination and strong purifying selection JF Science Advances JO Sci Adv FD American Association for the Advancement of Science SP eabb9153 DO 10.1126/sciadv.abb9153 VO 6 IS 27 A1 Li, Xiaojun A1 Giorgi, Elena E. A1 Marichannegowda, Manukumar Honnayakanahalli A1 Foley, Brian A1 Xiao, Chuan A1 Kong, Xiang-Peng A1 Chen, Yue A1 Gnanakaran, S. A1 Korber, Bette A1 Gao, Feng YR 2020 UL http://advances.sciencemag.org/content/6/27/eabb9153.abstract AB COVID-19 has become a global pandemic caused by the novel coronavirus SARS-CoV-2. Understanding the origins of SARS-CoV-2 is critical for deterring future zoonosis, discovering new drugs, and developing a vaccine. We show evidence of strong purifying selection around the receptor binding motif (RBM) in the spike and other genes among bat, pangolin, and human coronaviruses, suggesting similar evolutionary constraints in different host species. We also demonstrate that SARS-CoV-2’s entire RBM was introduced through recombination with coronaviruses from pangolins, possibly a critical step in the evolution of SARS-CoV-2’s ability to infect humans. Similar purifying selection in different host species, together with frequent recombination among coronaviruses, suggests a common evolutionary mechanism that could lead to new emerging human coronaviruses.