As many countries emerge from lockdowns, researchers are prepared to use genome sequencing to avoid an expected second wave of C

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问题     As many countries emerge from lockdowns, researchers are prepared to use genome sequencing to avoid an expected second wave of COVID-19 infections. Since the first whole-genome sequence of the new coronavirus, SARS-CoV-2, was shared online on 11 January, scientists have sequenced and shared some 32,000 viral genomes from around the world. Such a vast amount of data has allowed researchers to trace the origin of COVID-19 outbreaks in their countries and pinpoint when community transmission occurred.
    Now, countries that have successfully suppressed infections are entering the next phase of the COVID-19 pandemic—where there’s a risk of new cases appearing as social restrictions ease. Researchers say that genomics will be crucial to quickly track and control these outbreaks. Studies already show that outbreaks tend to be shorter and smaller when genomics is used to help contact tracing. "When there are few cases, genomics can very quickly tell you what you’re dealing with and therefore guide precision interventions," says Gytis Dudas, a consulting bioinformatician at the Gothenburg Global Biodiversity Centre in Sweden.
    Several places are particularly well placed to do that because they invested in genome sequencing early in the pandemic and have a relatively small number of cases. Researchers in New Zealand, and at least one state in Australia decided that they would aim to sequence most coronavirus genomes in their country or state. As SARS-CoV-2 spread around the world, distinct lineages began to form as viruses circulating in different regions gradually evolved. By comparing sequences, researchers can quickly rule out possible lines of transmission if two sequences don’t match, or link together cases that do.
    Scientists in the United Kingdom, the United States and other countries are also sequencing SARS-CoV-2 from a large proportion of cases there, but because their epidemics are still ongoing and case numbers are high, genomics is being used to monitor spread and help identify the source of some cases where contact tracing fails. But such interventions depend on broad sampling, and so in places where diagnostic testing is limited, there will also be gaps in the genomic data.
    But the use of genomic analysis to help contact tracing is largely restricted to high-income countries, says Meru Sheel, an epidemiologist at the Australian National University in Canberra. She would like to see genomics considered as a tool for outbreak responses in resource-limited countries in the Asia-Pacific region, as it was in the Democratic Republic of the Congo, Sierra Leone and Guinea during the Ebola outbreak.
The situations in the United Kingdom and the United States are mentioned to________.

选项 A、show that interventions require considerable sample data
B、demonstrate the importance of the genome sequence
C、introduce the transmission routes of cases
D、ask for resource support for researches

答案B

解析 例证题。根据题干关键词the United Kingdom the United States可定位至第四段第一句。该句前半句对英国、美国和其他国家的情况作了介绍:Scientists in the United Kingdom,the United States and other countries are also sequencing SARS-CoV-2 from a large proportion of cases there. 后半句表达转折:“but because their epidemics are still ongoing and case numbers are high. genomics is being used to monitor spread and help identify the source of some cases where contact tracing fails”. 即“但因为疫情仍在持续,且病例数量极多,基因组学也正被用于监测传播,并在追踪失败的情况下帮助确认一些病例的接触源头”。因此,提到这些国家是为了说明基因组学在各国的应用,展现了基因组序列的重要性,故B项正确。A、C、D项都不符合上下文,故排除。
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