Virus hunters: Discovering the evolutionary origins of SARS-CoV-2

Abstract

The likely animal source of SARS-CoV-2 remains speculative. A recent study published in Cell by Zhou et al. reported the detection of novel alpha- and betacoronaviruses, including SARS-CoV-2-related viruses in bats.

Figure 1

Key findings from Zhou and colleagues’ article (A) Schematic representation of the study design and key observations. Zhou et al. (2021) identified 17 alphacoronaviruses and 7 novel betacoronaviruses in 411 bat samples collected from Yunnan province, China. Four of seven detected betacoronaviruses were closely related to SARS-CoV-2, while the remaining three were related to SARS-CoV. RsYN04 receptor-binding domain (RBD) displayed weak binding affinity to human cellular receptor, angiotensin-converting enzyme 2 (ACE2). The RBD from betacoronavirus RpYN06 did not bind to ACE2. The newly discovered alphacoronavirus sequences included swine acute diarrhea syndrome CoV (SADS-CoV)-like and porcine epidemic diarrhea virus (PEDV)-like viruses. (B) Nucleotide identity of two bat-borne betacoronaviruses, RaTG13 and RpYN06, compared to SARS-CoV-2 (reference sequence: NC_045512). Whole-genome and gene-level percentage nucleotide identity reported by Zhou et al. (2021) are shown here. Figure was made using BioRender.com and Adobe Illustrator (v25.3).