大馬1251 wrote:
該報告是說：人類中最(恕刪)
A型只在武漢的」美國和澳洲人」身上發現，莫非住在武漢的只有這兩國人
個人積分：1794分
文章編號：77160520
個人積分：6分
文章編號：77160638
mindcry wrote:
報告裡面說起源武漢，...(恕刪)
到底是你英文不好，還是欺負另人英文不好？
你的紅字。
Forster and colleagues found that the closest type of COVID-19 to the one discovered in bats – type ‘A’, the “original human virus genome” – was present in Wuhan, but surprisingly was not the city’s predominant virus type.
Mutated versions of ‘A’ were seen in Americans reported to have lived in Wuhan, and a large number of A-type viruses were found in patients from the US and Australia.
紅字說明A類大量在美國和澳洲找到。
人可以有立場，但不可用說謊辯護你的立場。
個人積分：5393分
文章編號：77160698
個人積分：109分
文章編號：77160708
個人積分：36分
文章編號：77160799
個人積分：1024分
文章編號：77160844
個人積分：36分
文章編號：77160879
個人積分：476分
文章編號：77160917
個人積分：0分
文章編號：77161371
Zhou et al. (7) recently reported a closely related bat coronavirus, with 96.2% sequence similarity to the human virus. We use this bat virus as an outgroup, resulting in the root of the network being placed in a cluster of lineages which we have labeled “A.”
There are two subclusters of A which are distinguished by the synonymous mutation T29095C. In the T-allele subcluster, four Chinese individuals (from the southern coastal Chinese province of Guangdong) carry the ancestral genome, while three Japanese and two American patients differ from it by a number of mutations. These American patients are reported to have had a history of residence in the presumed source of the outbreak in Wuhan. The C-allele subcluster sports relatively long mutational branches and includes five individuals from Wuhan, two of which are represented in the ancestral node, and eight other East Asians from China and adjacent countries. It is noteworthy that nearly half (15/33) of the types in this subcluster, however, are found outside East Asia, mainly in the United States and Australia.
Two derived network nodes are striking in terms of the number of individuals included in the nodal type and in mutational branches radiating from these nodes. We have labeled these phylogenetic clusters B and C.
For type B, all but 19 of the 93 type B genomes were sampled in Wuhan (n = 22), in other parts of eastern China (n = 31), and, sporadically, in adjacent Asian countries (n = 21). Outside of East Asia, 10 B-types were found in viral genomes from the United States and Canada, one in Mexico, four in France, two in Germany, and one each in Italy and Australia. Node B is derived from A by two mutations
A complex founder scenario is one possibility, and a different explanation worth considering is that the ancestral Wuhan B-type virus is immunologically or environmentally adapted to a large section of the East Asian population, and may need to mutate to overcome resistance outside East Asia.
Type C differs from its parent type B by the nonsynonymous mutation G26144T which changes a glycine to a valine. In the dataset, this is the major European type (n = 11), with representatives in France, Italy, Sweden, and England, and in California and Brazil. It is absent in the mainland Chinese sample, but evident in Singapore (n = 5) and also found in Hong Kong, Taiwan, and South Korea.
February 2020, the first Brazilian was reported to have been infected following a visit to Italy, and the network algorithm reflects this with a mutational link between an Italian and his Brazilian viral genome in cluster C (SI Appendix, Fig. S1). In another case, a man from Ontario had traveled from Wuhan in central China to Guangdong in southern China and then returned to Canada, where he fell ill and was conclusively diagnosed with coronavirus disease 2019 (COVID-19) on 27 January 2020. In the phylogenetic network (SI Appendix, Fig. S2), his virus genome branches from a reconstructed ancestral node, with derived virus variants in Foshan and Shenzhen (both in Guangdong province), in agreement with his travel history. His virus genome now coexists with those of other infected North Americans (one Canadian and two Californians) who evidently share a common viral genealogy. The case of the single Mexican viral genome in the network is a documented infection diagnosed on 28 February 2020 in a Mexican traveler to Italy. Not only does the network confirm the Italian origin of the Mexican virus (SI Appendix, Fig. S3), but it also implies that this Italian virus derives from the first documented German infection on 27 January 2020 in an employee working for the Webasto company in Munich, who, in turn, had contracted the infection from a Chinese colleague in Shanghai who had received a visit by her parents from Wuhan. This viral journey from Wuhan to Mexico, lasting a month, is documented by 10 mutations in the phylogenetic network.
這篇報告還附了一個病毒基因的突變演化系譜：
局部放大：
還附圖說：
Phylogenetic network of 160 SARS-CoV-2 genomes. Node A is the root cluster obtained with the bat (R. affinis) coronavirus isolate BatCoVRaTG13 from Yunnan Province. Circle areas are proportional to the number of taxa, and each notch on the links represents a mutated nucleotide position. The sequence range under consideration is 56 to 29,797, with nucleotide position (np) numbering according to the Wuhan 1 reference sequence (8). The median-joining network algorithm (2) and the Steiner algorithm (9) were used, both implemented in the software package Network5011CS (https://www.fluxus-engineering.com/), with the parameter epsilon set to zero, generating this network containing 288 most-parsimonious trees of length 229 mutations. The reticulations are mainly caused by recurrent mutations at np11083. The 161 taxa (160 human viruses and one bat virus) yield 101 distinct genomic sequences. The phylogenetic diagram is available for detailed scrutiny in A0 poster format (SI Appendix, Fig. S5) and in the free Network download files.
簡單講，
就是這個系譜的起源是從中國雲南分離出來的蝙蝠病毒，
由這個蝙蝠病毒演化出A基因組，
A基因組又變異出B基因組，其間只經過兩次突變，
B基因組再變異出C基因組，其間的突變分支相當長。
B基因組當中有廣東一帶患者的，直接就是原來的基因組，也有日本、美國患者，這兩國患者則都經過多次突變而與祖代基因有異，可能是因為B基因組在東亞一帶的免疫和環境適應良好，在東亞以外則須經過突變才能生存。
C基因組經過相當長段的突變分支，有武漢患者，也有包括中國其他地區及東亞的患者，主要是新加坡，香港、台灣、南韓也有。另有將近一半是在東亞以外發現，主要是美國和澳洲，歐洲患者也主要都是這一型，還有從義大利傳過去的巴西、墨西哥。
作者還特別舉例說明一位加拿大患者的基因譜系可上溯自廣東福山和深圳的變種基因，一名墨西哥患者的基因譜系則可上溯義大利、德國慕尼黑、上海、武漢。從武漢到墨西哥，經歷了十次突變。
所以，樓主的貼文根本是錯讀原作的意思。
單純只看基因譜系圖，
也可以清楚看出中國武漢的B型是直接源自根源的A型，完全與美國的病毒型無關，
A型的祖代基因色譜中也沒有美國基因型的藍色，
美國基因型有些是從A型突變而來，有些則是源自中國的B型。
個人積分：87分
文章編號：77161446
turtlins wrote:
節錄這篇報告的摘要中(恕刪)
這是關鍵，你沒有摘譯
研究發現，在武漢的病患樣本發現了A類病毒，但是大規模傳播的為B類。令人驚訝的是，在武漢居住過的美國人身上發現了A類病毒，來自美國和澳大利亞的病患體內也發現了大量的A類病毒。中國乃至整個東亞範圍內，傳播最廣泛的是A類病毒的變異體，為B類病毒。
對於病毒來源問題，劍橋大學Peter Forster博士給出了自己的看法，目前仍無法就病毒來源給出一個明確答案。
回到理性，病毒是人類共同的敵人，病毒來自哪裡並不重要。當年西班牙病毒死了5000萬人，來源在美國，為何沒有引起這麼大反應 ?
因為英美政客要玩雙標，挑動民粹來掩飾自己的無能。
