bioRXiv: 新冠病毒的毒力正逐渐减弱？一基因片段开始丢失

生物医学预印杂志bioRXiv在3月12日发表了新加坡的研究团队的一篇论文（尚未经过同行评审），该研究发现，在新加坡检测到的新冠病毒阳性患者中，有多名患者体内的新冠病毒毒株出现了一段382碱基的缺失，该缺失片段完整覆盖了阅读编码框ORF8。而根据2003爆发的SARS历史数据，2003年的SARS病毒在疫情后期也出现了ORF8的缺失，该缺失导致了SARS病毒毒力作用的减弱，使得病毒更适合和宿主共存。因此文章从2003年的SARS病毒的现象推测新冠病毒感染人群一段时间后出现了ORF8缺失的病毒毒株，毒力也逐渐减弱。

To date, the SARS-CoV-2 genome has been considered genetically more stable than SARS-CoV or MERS-CoV. Here we report a 382-nt deletion covering almost the entire open reading frame 8 (ORF8) of SARS-CoV-2 obtained from eight hospitalized patients in Singapore. The deletion also removes the ORF8 transcription-regulatory sequence (TRS), which in turn enhances the downstream transcription of the N gene. We also found that viruses with the deletion have been circulating for at least four weeks. During the SARS-CoV outbreak in 2003, a number of genetic variants were observed in the human population, and similar variation has since been observed across SARS-related CoVs in humans and bats. Overwhelmingly these viruses had mutations or deletions in ORF8, that have been associated with reduced replicative fitness of the virus. This is also consistent with the observation that towards the end of the outbreak sequences obtained from human SARS cases possessed an ORF8 deletion that may be associated with host adaptation. We therefore hypothesise that the major deletion revealed in this study may lead to an attenuated phenotype of SARS-CoV-2.

原始出处：

Yvonne Su, Danielle Anderson, Barnaby Young, Feng Zhu, Martin Linster,Shirin Kalimuddin, Jenny Low, Zhuang Yan, Jayanthi Jayakumar, Louisa Sun, Gabriel Yan, Ian Mendenhall, Yee-Sin Leo, David Lye, Lin-Fa Wang, Gavin Smith.Discovery of a 382-nt deletion during the early evolution of SARS-CoV-2.doi: https://doi.org/10.1101/2020.03.11.987222

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