British scientists have discovered novel coronavirus has evolved into 3 different strains during the spread of the world, and is “rapidly mutating to adapt to the immune system resistance of different populations”. Studies have also shown that virus variants found in some Americans are most closely related to viruses found in bats.
Researchers from Cambridge University mapped the initial spread of the new coronavirus (covid-19) in humans and found three different but closely related variants, the Sun reported on April 10.
Scientists have reconstructed the early evolutionary path of the new coronavirus, from the most affected areas in China to Europe and North America. The results were published in the latest issue of the proceedings of the National Academy of Sciences (PNAs).
Dr. Peter Forster, a geneticist at Cambridge University and the lead author of the research paper, said that through the analysis of the first 160 complete viral genome sequences found in patients, the closest variation found in bats was mainly found in patients from the United States and Australia, rather than in patients from Wuhan, China.
Three different strains of new coronavirus in global transmission
They used sample data collected from around the world between December 24, 2019 and March 4, 2020. Data show that there are three distinct but closely related variants of the new coronavirus, known as a, B, and C.
The researchers found that the closest type of coronavirus found in bats is type A, the original human virus genome. The virus genome exists in Wuhan, but it is not the main virus type in Wuhan.
The mutant a virus was found in the Americans living in Wuhan, and a large number of a virus was also found in patients from the United States and Australia.
The main virus type of Wuhan patients is type B, which exists in patients all over East Asia. However, if there is no further variation, it will not spread too much outside the region.
The researchers said the C virus, the main European type, was found in early patients from France, Italy, Sweden and the UK. The type C virus did not appear in the Chinese mainland samples in the study, but was found in Singapore, Hong Kong and South Korea.
The analysis also showed that one of the earliest routes of introduction of the virus into Italy was through the first recorded German patient on January 27, and the other early Italian route of infection was related to “Singapore clustering”.
The results show that type A virus is most closely related to the virus found in bats and pangolins, which the researchers describe as the source of the outbreak. Type B virus is derived from type A, separated by two mutations, and then type C, in turn, is the “daughter” of type B.
“Social isolation” can effectively inhibit the spread of the virus (on the left is the speed of transmission without measures, on the right is the speed of transmission with measures)
Foster said the virus had too many rapid mutations to track the entire covid-19 family tree. “But we use a mathematical network algorithm to visualize all plausible trees at the same time. What these techniques are best known for is the use of DNA to map prehistoric migration. We think it’s the first time it’s been used to track the infection of a coronavirus like covid-19. “
Experts warn that the new coronavirus is constantly mutating rapidly to adapt to immune system resistance in different populations.
Forster said their method could be applied to the sequencing of the latest coronavirus genome to help predict future hot spots in global disease transmission and surge.
The researchers used the phylogenetic network method to observe the evolutionary relationship between biological entities, so that hundreds of evolutionary trees can be visualized in a simple chart at the same time.