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  3. DNA sequences from some of the most deadly pathogens(病原体)known to man can be

DNA sequences from some of the most deadly pathogens(病原体)known to man can be

游客2023-07-05  42
问题     DNA sequences from some of the most deadly pathogens(病原体)known to man can be bought over the Internet, the Guardian has discovered.
    In an investigation which shows the ease with which terrorist organizations could obtain the basic ingredients of biological weapons, this newspaper obtained a short sequence of smallpox(天花)DNA. The deadly virus has existed only in laboratories since being eradicated from the world’ s population 30 years ago.
    The DNA sequence of smallpox, as well as other potentially dangerous pathogens such as poliovirus and 1918 flu are freely available in online public databases. So to build a virus from scratch, a terrorist would simply order consecutive lengths of DNA along the sequence and glue them together in the correct order. This is beyond the skills and equipment of the kitchen chemist, but could be achieved by a well-funded terrorist with access to a basic lab and PhD-level personnel.
    One study estimated that because most people on the planet have no resistance to the extinct virus, an initial release which infected just 10 people would spread to 2.2 million people in 180 days.
    The DNA sample we ordered had, at our request, three small modifications to render it harmless before it was sent by post to a residential address in London. The company has conceded that it was not aware it was sending out a sequence of modified smallpox DNA.
    There are legitimate reasons for researchers to buy lengths of DNA from pathogens, for example in developing treatments or vaccines against them. However, because this industry is so new and unregulated, companies are selling custom-made DNA without making thorough checks on the identities of the people who are placing the orders or what the sequences are.
    Of the four main companies operating in the UK, none currently screens all their DNA orders. There are 39 companies operating in North America and not all screen their orders. [br] The company whose DNA Samples we ordered______.
选项 A、did not knon what is really sent out then
B、has admitted it knew what it was really doing
C、was a new one in this industry
D、sent out the sample DNA to an office in London
答案 A
解析 细节题。文章倒数第三段最后指出The company has conceded that it wasnot aware it was sending out a sequence of modified smallpox DNA．意为这家公司承认当时并没有意识到送出的是一段改变了序列的天花DNA。由此可判断这家公司并不知道当时发生了什么，现在才知道。故答案A正确，B错误。选项C在文中没有提及：根据…sent by post to a residential address in London…可排除选项D。故选A。
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