研究在新冠病毒中发现新的基因突变。这一发现有什么意义？

For a virus, spreading for a few months and reaching more than 3 million hosts is a long time span to evolve and change.

传播数月并感染300多万人足以让一种病毒进化、改变。

Some viruses - like influenza - mutate a lot, meaning that we need to update vaccines yearly to remain on top of the spread of seasonal flu. Meanwhile, the coronavirus that has caused the current COVID-19 pandemic has stayed relatively stable, and it seems to be mutating much more slowly than influenza.

流感等病毒发生了很多变异，我们需要每年更新疫苗来控制季节性流感的传播。同时，导致本次疫情的冠状病毒一直相对稳定，好像比流感的变异速度慢得多。

This is great news for vaccine development and for the scientists who are closely studying the virus. But that doesn't mean it's not mutating at all.

这对疫苗研发和仔细研究这种病毒的科学家来说是个好消息，但并不意味着病毒就一点都没有发生突变。

Two new studies have recently been released analysing SARS-CoV-2 mutations. One study, from Arizona State University, discovered a large DNA deletion in a virus sample taken from a patient in Tempe.

最新发布的两项新的研究分析了新冠病毒的突变。其中亚利桑那州立大学进行的研究在从坦佩市一位病人体内采集的病毒样本中发现了一大段DNA缺失。

The second study, currently still a pre-print from the Los Alamos National Laboratory, tracked mutations throughout the outbreak, and hypothesised that one strain of the virus is more infectious than the original Wuhan strain.

另外一项研究目前还只是洛斯阿拉莫斯国家实验室的预印本，这项研究在整个疫情期间追踪突变，研究人员猜测有一种病毒比武汉的原始病毒传染性更强。

The Arizona study generated three full-length SARS-CoV-2 genomes from a series of samples; they found that one of these genomes, which they've named AZ-ASU2923, had a large deletion - 81 DNA base pairs - in a gene called ORF7a.

亚利桑那州的研究从一系列样本中获得了三个新冠病毒全长基因组，他们将其中一个命名为AZ-ASU2923，发现它的ORF7a基因有81个DNA碱基对的一大段缺失。

The ORF7a gene creates an accessory protein, which helps the virus infect, replicate and spread inside the human host. Specifically, the protein is thought to help the virus to evade our immune system and kill the cell once the replication process is complete.

ORF7a基因产生辅助蛋白，帮助病毒在人体内感染、复制和传播。具体说来，这种蛋白质被认为能帮助病毒避开我们的免疫系统，一旦完成复制就会杀死细胞。

"One of the reasons why this mutation is of interest is because it mirrors a large deletion that arose in the 2003 SARS outbreak," says one of the researchers, virologist Efrem Lim from Arizona State University.

亚利桑那州立大学的病毒学家Efrem Lim 也是其中一位研究人员，他说：“这种突变很重要的一个原因是它和2003年爆发非典时出现的大段缺失很像。”

Right now, we don't know how this mutation would change the coronavirus, and the researchers are investigating. Past research on similar genes and the fact it's only been found in a single individual, suggest that this deletion probably isn't great news for the virus.

目前我们不知道这种突变会对冠状病毒有什么影响，研究人员正在对此进行调查。过去对类似基因进行的研究和只在一个人身上发现这种情况的事实说明，这种缺失对病毒来说可能不是一个好消息。