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  3. Lonely people, it seems, are at greater risk than the gregarious of developing illnesses associated with chronic inflammation, s

Lonely people, it seems, are at greater risk than the gregarious of developing illnesses associated with chronic inflammation, s

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问题     Lonely people, it seems, are at greater risk than the gregarious of developing illnesses associated with chronic inflammation, such as heart disease and certain cancers. A paper published last year in the Public Library of Science, Medicine, shows the effect on mortality of loneliness is comparable with that of smoking and drinking after examining the results of 148 previous studies and controlled for factors such as age and pre-existing illness.
    Steven Cole of the University of California, Los Angeles, thinks he may know why this is so. He told the American Association for the Advancement of Science meeting in Washington, D.C., about his work studying the expression of genes in lonely people. Dr. Cole harvested samples of white blood cells from both lonely and gregarious people. He then analysed the activity of their genes, as measured by the production of a substance called messenger RNA. This molecule carries instructions from the genes telling a cell which proteins to make. The level of messenger RNA from most genes was the same in both types of people. There were several dozen genes, however, that were less active in the lonely, and several dozen others that were more active. Moreover, both the less active and the more active gene types came from a small number of functional groups.
    Broadly speaking, the genes less active in the lonely were those involved in staving off viral infections. Those that were more active were involved in protecting against bacteria. Dr. Cole suspects this could help explain not only why the lonely are iller, but how, in evolutionary terms, this odd state of affairs has come about.
    The crucial bit of the puzzle is that viruses have to be caught from another infected individual and they are usually species-specific. Bacteria, in contrast, often just lurk in the environment, and may thrive on many hosts. The gregarious are therefore at greater risk than the lonely of catching viruses, and Dr. Cole thus suggests that past evolution has created a mechanismwhich causes white cells to respond appropriately. Conversely, the lonely are better off ramping up their protection against bacterial infection, which is a bigger relative risk to them.
    What Dr. Cole seems to have revealed, then, is a mechanism by which social environment reaches inside a person’ s body and tweaks its genome so that it responds appropriately. It is not that the lonely and the gregarious are genetically different from each other. Rather, their genes are regulated differently, according to how sociable an individual is. Dr. Cole thinks this regulation is part of a wider mechanism that tunes individuals to the circumstances they find themselves in.  
Broadly speaking, the genes more active in the lonely
选项 A、helped to avoid infections resulting from viruses.
B、participated in guarding against bacteria.
C、came from a few different functional groups.
D、existed only as a small group.
答案B
解析 细节题。根据题干信息定位到第三段的前两句。这两句讲述孤独的人体内活性较低的基因是那些帮助人们避开病毒感染的基因。而那些活性较高的基因帮助人们抵抗细菌，因此答案为B项。文中提到避开病毒感染的基因是孤独的人体内活性较低的基因，故排除A项。第二段末句说无论是活性较高的基因还是活性较低的基因都来自少数功能群，与C项矛盾。D项在原文未提及，故排除。
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