首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
(1)That smoking causes lung cancer is well established. But what causes smoking? This is the question at the heart of a study pu
(1)That smoking causes lung cancer is well established. But what causes smoking? This is the question at the heart of a study pu
admin
2016-11-03
105
问题
(1)That smoking causes lung cancer is well established. But what causes smoking? This is the question at the heart of a study published in Nature by a group of researchers who work at deCODE, an Icelandic genomics company. They do not, quite, answer it. But they do think they have the answer to the related question of why some smokers smoke in moderation whereas others are rarely found without a fag in their hands—and thus why some people are, genetically speaking, more susceptible to lung cancer than others.
(2)That answer lies in part of human chromosome 15, and depends on what is known as allele T of SNP rsl051730. A SNP, or single-nucleotide polymorphism, to give its full name(the short version is pronounced "snip"), is a place where genomes routinely differ from one another by a single genetic letter.
(3)In this case, the variation happens inside a gene for one of the receptor molecules that nicotine attaches itself to when it produces its buzz. Based on a study of 13,945 Icelandic smokers, deCODE’s researchers showed that having a T in the appropriate part of the gene correlates very strongly indeed with being a heavy smoker. The team estimates that the chance of their being wrong is less than one in a thousand trillion.
(4)Not surprisingly, having the T variant also correlates with the chance of a smoker getting lung cancer. Each copy(there may be none, one or two, since one can come from a person’s father and one from his mother)increases that chance by 30%. The T variant does not, however, increase the likelihood that someone will take up smoking in the first place. That is either a matter of free will or, if it is genetic, is controlled by genes somewhere else. It all looks neat and simple—and extremely plausible. Genes promote smoking; smoking promotes cancer. However, it might be wrong, for another paper in Nature, and a third in its sister journal Nature Genetics, report similar studies that have drawn rather different conclusions.
(5)Paul Brennan and Christopher Amos both agree mat something significant is going on in the part of chromosome 15 studied by deCODE. But they have concluded that genetic variation there acts directly on a person’s susceptibility to lung cancer, rather than acting indirectly by modifying his smoking behavior. That does not mean the gene or genes in question actually cause lung cancer. Rather, it means that they amplify the effects of smoking instead of the amount of smoking.
(6)Like deCODE, both Dr. Brennan(who works at the International Agency for Research on Cancer, in France)and Dr. Amos(who works at the University of Texas)identified rsl051730 as an important SNP. Unlike deCODE, though, both think a second SNP, rs8034191, is involved as well. That, and the fact that the region of chromosome 15 under scrutiny has two other nicotine-receptor genes in it, suggests the situation may indeed be more complex.
(7)On top of this, Dr. Brennan and Dr. Amos both used a different method from deCODE’s. They compared lung-cancer patients directly with otherwise similar cancer-free smokers, in what is known as a case controlled study, and concluded that genetic variants in the nicotine-receptor-rich part of chromosome 15 are changing not smokers’ behavior, but their susceptibility to cancer. Moreover, Dr. Brennan also claims to have discovered an increased susceptibility to lung cancer in non-smokers with the relevant SNPs, though his sample size is small and his result is not supported by Dr. Amos’s work.
(8)These contradictory conclusions are both puzzling and intriguing. DeCODE has one further piece of evidence in its favor. Besides the correlation with lung cancer, the T variant also seemed to correlate with peripheral arterial disease, another common side-effect of smoking. On the other hand, the firm also acknowledges that the link it thinks it has discovered does not account for the whole of the risk of smoking-induced lung cancer. What is not in doubt, however, is that there is some sort of a link between genetics and lung cancer.
(9)That raises interesting issues, particularly as genetic testing becomes easier. DeCODE has already announced it will add rsl051730 to the standard screen it offers to those who wish to know their susceptibility to diseases. The day is not far off, therefore, when those who take the essentially irrational decision to start smoking tobacco will be able to find out in advance exactly how foolish they are being.
The results of the study done by Paul Brennan and Christopher Amos _____.
选项
A、have shown a completely contradictory situation with the study done by deCODE
B、suggest that the situation may be more complex than deCODE has identified
C、show that rs8034191 instead of rs1051730 is related to the susceptibility to lung cancer
D、smoking behavior is modified by genetic variations in the region of chromosome 15
答案
B
解析
第5、6段提到Paul Brennan和Christopher Amos所做的研究与deCODE公司结果的一些不同之处和相似之处,并在第6段末句总结得出,实际情况可能更加复杂,B符合此意,故正确。A中的completely太绝对:C中的instead of与第6段倒数第2句中的involved as well不符;第5段第2句中的rather than否定了…modifying his smoking behaviour,故D错误。
转载请注明原文地址:https://kaotiyun.com/show/1c7O777K
0
专业英语八级
相关试题推荐
Morepeopledieoftuberculosis(结核病)thanofanyotherdiseasecausedbyasingleagent.Thishasprobablybeenthecaseinquit
SomepeoplehavedrawntheconclusionfromBowlby’sworkthatchildrenshouldbesubjectedtodaycarebeforetheageofthree
SomepeoplehavedrawntheconclusionfromBowlby’sworkthatchildrenshouldbesubjectedtodaycarebeforetheageofthree
Whatwillbetheimpactofaglobalcomputernetworkonculturalforms?Theconstructionofexclusiveinformationsocietieshas
Accordingtolegend,theancientOlympicGameswerefoundedbyHeracles,asonofZeus.YetthefirstOlympicGamesforwhich
Accordingtolegend,theancientOlympicGameswerefoundedbyHeracles,asonofZeus.YetthefirstOlympicGamesforwhich
ThefirstBritishColonyestablishedinAmericain1607is
Aco-educationalschoolofferschildrennothinglessthanatrueversionofsocietyinminiature.Boysandgirlsaregiventhe
Necessarymeditationsontheactual,includingthemeanbread-and-cheesequestion,dissipatedthephantasmalforawhile,andco
Despitethefactthattodayvirusesareknowntocausecancerinanimalsandincertainplants,whereexistsagreatreluctance
随机试题
慢性肾炎患者若出现胸腔积液,则考虑最可能发生了
A.自我试验B.天然试验C.强迫试验D.临床试验E.志愿试验由于自然灾害和战争可形成大面积的研究样本群称为()
休克患者并发休克肺时的典型表现是:
某公司拟在市区新建1个加油站,其总平面布局周边民用建筑等相关信息如下图所示。站内拟建1栋站房,1个罩棚(采用不燃建筑构件,净高6m),5个埋地油罐,4台加油机;拟采用加油和卸油油气回收系统。该加油站选址用地西临城市主干路,北临某幼儿园建筑,南临某住宅楼,东
“黑箱”,是控制论中的概念,意为在认识上主体对其内部情况全然不知的对象。“科技黑箱”的含义与此有所不同,它是一种特殊的存贮知识、运行知识的设施或过程,使用者如同面对黑箱,不必打开,也不必理解和掌握其中的知识,只需按规则操作即可得到预期的结果。例如
某居民小区边要建一个移动通信基站.有居民认为电磁辐射会危害小区安全,还有不少居民对此表现出抵触、排斥的情绪。你是居委会的工作人员。领导让你负责处理此事。你会怎么办?
关于高级人民法院管辖的案件不包括
构成派
Theterm"leadership"isoneofthemostdifficultinan【M1】______educationaladministration.Tosome,aleaderissimpleonew
A、Hethinksthelakeisverywide,too.B、Hewantstoswimacrossthelake.C、Hedoesn’tthinkthelakeisverywide.D、Hedoesn
最新回复
(
0
)