A new study undertaken by researchers in the US and China has found no evidence that the SARS-CoV-2 virus has evolved from a pangolin coronavirus (pangolin-CoV-2020). This work contradicts an earlier study that was published last week in Nature, which suggested that pangolins may have been an intermediate host for SARS-CoV-2.
The study that was published last week searched for viruses that were similar to SARS-CoV-2 in the lung tissue of Malayan pangolins that were confiscated by customs during March and August of last year, and four Chinese pangolins. They isolated a pangolin virus that shared a high amino acid identity with SARS-CoV-2, suggesting they have the potential to act as an intermediate host of SARS-CoV-2.
However, a new study has come to a different conclusion. The researchers assembled the genome of a coronavirus in three sick Malayan pangolins. While the analysis shows that pangolin-CoV-2020 is genetically related to SARS-CoV-2, and a group of bat coronaviruses, the data did not support that SARS-CoV-2 came directly from the pangolin coronavirus.
This new study was conducted using metagenomic sequencing and de novo viral genome assembly from the three sick pangolins. They then pooled sequences from the three samples and assembled the draft genome of the pangolin coronavirus. The researchers said the genomic analysis suggested the pangolin-CoV-2020 had high identity with both Bat-CoV-RaTG13 and SARS-CoV-2 and certain sequences corresponded The sequence for regions between SARS-CoV-2 and Bat-CoV-RaTG13 suggested that they were more similar than the pangolin coronavirus, however, researchers noted that although their study did not support the hypothesis that pangolins were the intermediate host for the emergence of SARS-CoV-2, they do not exclude the possibility that other coronaviruses could be circulating in pangolins.