The research report entitled "novel coronavirus Genome Network Analysis of novel coronavirus Genome" was written by British and German scholars and published in the Proceedings of the National Academy of Sciences (PNAS) on April 8th. Researchers mapped novel coronavirus's early "evolutionary path" in human body through gene network technology. In this study, the first batch of 160 complete virus genomes obtained from patients were analyzed, and different virus lineages produced by novel coronavirus mutation were obtained.
Global Distribution of "A, B, C" According to Peter Forster, a geneticist at Cambridge University and the main author of the report, researchers can't completely trace the family lineage of the virus because of too many rapid mutations, so they use mathematical network algorithms and find out all possible lineages at the same time. Foster said that the most well-known use of this technology is to track the movements of prehistoric humans through DNA.
The research team extracted 160 samples collected from GISAID database from February 24th, 1965, 438+09 to March 4th, 2020, and found three COVID-19 types with close genetic pedigree, which were divided into three types: A, B and C, among which the more primitive strain A was the closest to that found in bats. Although type A also appears in Wuhan, it is not the most common strain in Wuhan.
The study pointed out that this strain was also found among Americans who once lived in Wuhan. It was found that among the infected people in the United States and Australia, type A was more common, while the B strain mutated from type A was more common in Wuhan. Generally speaking, type B is more common in East Asia and rarely spreads to other regions without mutation. The researchers analyzed that the reason may be the genetic "founder effect" in Wuhan, or that people outside East Asia are more "resistant" to this kind of virus. Type C is a variant of type B, which mainly appears in Europe and is also found in early patients in France, Italy, Sweden and Britain. Although there is no type C in the samples of China patients studied, it is found in Singapore, Hongkong and South Korea.
Basically, in the first stage of the outbreak, the most common types outside East Asia, such as Europe, America and Australia, are Type A and Type C. Type B is the most common in East Asia. Type C appeared in Singapore in the early stage, and it is also a common strain type among the first infected people in Europe.
This research report has been widely discussed on social media in China, and people think it can prove that COVID-19 is not from Wuhan. Peter Forster, one of the main authors of the report, said in an interview with the Global Times reporter that in view of the political disputes between China and the United States, he understood that the topic of the origin of the virus was a "hot potato", but this report and their current research could not give a clear explanation.
As for why virus A was not widely infected in Wuhan, Foster's analysis may be that "A can't adapt to the local immune system", so it mutated into B. On the other hand, the infected strain of A adapted to the immune systems of the United States and Australia.
The research team is currently expanding its research sample to 100 1 virus genome. Although the research results have not yet been released, Foster said that the first batch of infections and virus transmission occurred between mid-September last year and early February.
The researchers believe that the analysis method using gene network technology will help to predict the location of the next outbreak. Take Italy for example. At first, the Italian "patient 1" was thought to be infected by contact with acquaintances who went to Wuhan. But the latter did not detect the virus, and the search for "patient zero" was fruitless. Foster's research found that the earliest infection case in Italy may be traced back to a German patient who was notified of the infection on June 27th, 65438, and another initial infection case in Italy was related to "Singapore infection group".