Evolution of Coronavirus, seen from Wuhan

Last week, on March 3, 2020, an article (accepted manuscript) was published in the National Science Review. The article, titled “On the Origin and Continuing Evolution of SARS-CoV-2”, was authored by scientists from Peking University, Chinese Academy of Sciences, Peking Union Medical Collage, and Shanghai University. The authors discussed their findings of a single nucleotide mutation of the SARS-CoV-2 in the early days of the epidemic, or single nucleotide polymorphism (SNP). According to the authors, this new mutated type, given the name L-Type, is more “aggressive” than the ancestral S-Type. While L-Type is sending more people to the hospitals, the S-Type is one that is spreading more widely. Hence the apparent larger number of people with milder cases of Covid-19. (1) [NOTE: for a summary of the findings, see Coronavirus Epidemic Update 31, 2:21]

Another scientist, in his response to the article by the Chinese scientists, pointed out that when an RNA virus changes hosts, mutation often happens because the virus needs to adopt to the new host. In the case of SARS-CoV-2, that new host is us! (2)

Back in 2004, when the first SARS were happening, scientists already wrote about the viral evolution of coronavirus, and noted that among the emerging viruses, majority are RNA rather than DNA viruses. RNA’s higher mutation rate is one reason why RNA viruses adopt better to new hosts than DNA viruses, and accounts for its agility to cross species. (3)

Looping back to my first blog on the Global Virome Project, it is more apparent now than ever the need to invest in the project to map the viruses in the animal kingdom and other kingdoms, such as the marine viruses, to gain data and knowledge in the understanding of future emerging viral diseases.

~~ You Jia Zhu

1. Xiaolu Tang, Changcheng Wu, Xiang Li, Yuhe Song, Xinmin Yao, Xinkai Wu, Yuange Duan, Hong Zhang, Yirong Wang, Zhaohui Qian, Jie Cui, and Jian Lu, “On the origin and continuing evolution of SARS-CoV-2”, National Science Review, March 3, 2020.

2. “Expert Reaction to Study Looking at Whether There Are Two Strains of the Novel Coronavirus”, Science Media Center, March 4, 2020.

3. Edward C. Holmes and Andrew Rambaut, “Viral Evolution and the Emergence of SARS Coronavirus”, The Royal Society, July 29, 2004.