阅读理解
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 preexisting 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 mechanism which 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.
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 mechanism which 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.
单选题
16.What risk may lonely people run according to the first paragraph?
【正确答案】
C
【答案解析】细节题。根据题干信息定位到第一段。本段主要介绍了《科学公共图书馆——医学》上一篇论文的观点，与爱交际的人相比，孤独的人似乎患与慢性炎症相关的疾病的风险更大，孤独对死亡率的影响能与抽烟和酗酒相提并论。由此可见，C项“他们可能成为慢性疾病的受害者”符合题意，为正确答案。
单选题
17.Dr. Cole made an analysis of the activity of the genes by_____.
【正确答案】
A
【答案解析】细节题。根据题干信息定位到第二段的第三、四句。从这两句可知，柯尔博士从孤独的人和爱交际的人那里收集了白细胞样本，然后靠测量一种叫作信使RNA的物质的数量分析了他们基因的活性，或者说通过测量信使RNA的含量来分析基因活性，故A项符合题意，为正确答案。
单选题
18.Broadly speaking, the genes more active in the lonely_____.
【正确答案】
B
【答案解析】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。
单选题
19.What can we know about viruses and bacteria from the fourth paragraph?
【正确答案】
D
【答案解析】细节题。根据题干信息定位到第四段。根据本段前三句可知，病毒只有通过另一个已被感染此病毒的人才能传染给某个人，并且病毒通常有其一对一的特殊宿主。相比之下，细菌经常潜伏在周围环境中，并且宿主众多。所以爱交际的人比孤独的人更易感染病毒。由此可见，病毒较之细菌对爱交际的人的威胁更大，故D项为正确答案。
单选题
20.What message does Dr. Cole seem to convey by the mechanism?
【正确答案】
B
【答案解析】推断题。根据题干信息定位到最后一段。由本段前三句可知，柯尔博士似乎已经揭示出这样一种机制，社交环境可以影响人们体内的生化活动，调整人体内的基因组以让其做出恰当的反应。这并非说孤独的人和爱交际的人在基因上有所不同，而是根据交际程度的不同，这两种人以不同的方式调控各自的基因。归纳上述内容可推断，交际程度能调整人的基因组，使它得以良好运作，故B项为正确答案。