Passage1Lonelypeople,itseems,a-考网

Passage 1

Lonely people, it seems, are at greater risk than the gregarious of developing illnessesassociated with chronic inflammation, such as heart disease and certain cancers. A paper publishedlast year in the Public Library of Science, Medicine, shows the effect on mortality of loneliness iscomparable with that of smoking and drinking after examining the results of 148 previous studiesand 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 ofwhite blood cells from both lonely and gregarious people. He then analysed the activity of theirgenes, as measured by the production of a substance called messenger RNA. This molecule carriesinstructions from the genes telling a cell which proteins to make. The level of messenger RNA frommost genes was the same in both types of people. There were several dozen genes, however, thatwere less active in the lonely, and several dozen others that were more active. Moreover, both theless 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 viralinfections. Those that were more active were involved in protecting against bacteria. Dr. Colesuspects this could help explain not only why the lonely are iller, but how, in evolutionary terms, thisodd state of affairs has come about.

The crucial bit of the puzzle is that viruses have to be caught from another infected individualand they are usually species-specific. Bacteria, in contrast, often just lurk in the environment, andmay thrive on many hosts. The gregarious are therefore at greater risk than the lonely of catchingviruses, and Dr. Cole thus suggests

A.measuring the level of messenger RNA
B.calculating the number of more active gene types
C.instructing the production of certain proteins
D.comparing less active genes with more active ones

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答案： A

本题解析：

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，Cole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。B项和D项在原文中没有提及．可排除。原文提到的是信使RNA携带者基因上的指令．这些指令告诉细胞生产哪类蛋白质，显然这是对信使RNA的介绍．并不是分析基因活性的方法．故C项“对生产某种蛋白质下达指令”错误。