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看到PNAS这个关于covid19的基因分析：武汉的病毒是中国外变异的

原文链接：https://forum.iask.ca/threads/900817/

木尘子 : 2020-04-12#1
www.pnas.org

Phylogenetic network analysis of SARS-CoV-2 genomes

This is a phylogenetic network of SARS-CoV-2 genomes sampled from across the world. These genomes are closely related and under evolutionary selection in their human hosts, sometimes with parallel evolution events, that is, the same virus mutation emerges in two different human hosts. This makes...
www.pnas.org www.pnas.org
we find three central variants distinguished by amino acid changes, which we have named A, B, and C, with A being the ancestral type according to the bat outgroup coronavirus. The A and C types are found in significant proportions outside East Asia, that is, in Europeans and Americans. In contrast, the B type is the most common type in East Asia, and its ancestral genome appears not to have spread outside East Asia without first mutating into derived B types, pointing to founder effects or immunological or environmental resistance against this type outside Asia. The network faithfully traces routes of infections for documented coronavirus disease 2019 (COVID-19) cases, indicating that phylogenetic networks can likewise be successfully used to help trace undocumented COVID-19 infection sources, which can then be quarantined to prevent recurrent spread of the disease worldwide.

Roaringmouse : 2020-04-12#2
B是A突变过来的，有两个突变，冠状病毒突变速度大概半个月有一个突变，B从A有两个突变，也就是说A到B至少要用一个月时间，武汉第一例是B，在12月24发现，那么A至少在11月24日出现，但传给第一例的那个人也应该是B，时间至少往前移到10月24，再加上2周潜伏期，至少要到10月10日左右武汉就有病毒感染存在。不知道武汉那个运动会是什么时候开的

木尘子 : 2020-04-12#3
武汉运动会是10月18日开始，运动员一般提前到 所以在18日之前就到。也有可能是澳洲火山大火烧死几万动物引起什么东西。