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
Nearly six years after the sequence of the human genome was sketched out, one might assume that researchers had worked out what
Nearly six years after the sequence of the human genome was sketched out, one might assume that researchers had worked out what
admin
2012-07-11
35
问题
Nearly six years after the sequence of the human genome was sketched out, one might assume that researchers had worked out what all that DNA means. But a new investigation has left them wondering just how similar one person’s genome is to another’s.
Geneticists have generally assumed that your string of DNA "letters" is 99. 9%identical to that of your neighbor’s, with differences in the odd individual letter. These differences make each person genetically unique — influencing everything from appearance and personality to susceptibility to disease.
But hold on, say the authors of a new study published in Nature. They have identified surprisingly large chunks of the genome that can differ dramatically from one person to the next. "Everyone has a unique pattern," says one of the lead authors Matthew Hurles at the Wellcome Trust Sanger Institute in Cambridge, U.K.
The differences in question — made up of stretches of DNA that span tens to hundreds of thousands of chemical letters — are called "copy-number variants", or CNVs. Within a given stretch of DNA, one person may carry one copy of a DNA segment; another may have two, three or more. The region might be completely absent from a third person’s genome. And sometimes the segments are shuffled up in different ways.
These variable regions received short shrift (承认) for many years. When the human genome sequence was pieced together, they were largely glossed over, because researchers were focused on finding one overarching reference sequence — and because the repetitive nature of the segments makes them hard to sequence. "It was swept under the rug," says Michael Wigler, who is also mapping CNVs at Cold Spring Harbor Laboratory, New York.
The new study, led by Hurles and Stephen Scherer of the Hospital for Sick Children in Toronto, Canada, and their colleagues is the most detailed attempt to find how CNVs are scattered across the whole human genome. To do this, they compared genome chunks from 270 people of European, African or Asian ancestry. They found nearly 1,500 such regions, taking up some 12%of the human genome. That doesn’t mean that your DNA is 12%different from mine (or 88%similar), because any two people’s DNA will differ at only a handful of these spots.
According to the team’s back-of-the-envelope calculations, one person’s DNA is probably 99. 5%similar to their neighbor’s, or a bit less. "I’ve tried to do the calculation and it’s very complicated," says Hurles. "It all depends on how you do the accounting."
The answer is also unclear because researchers think that there are many more variable blocks of sequence that are 10,000 or 1,000 letters long and were excluded from the current study.
Researchers find the way CNVs are spread by______.
选项
A、doing the back-of-the-envelope calculations
B、analyzing the differences in different people’s genome
C、looking for unique regions of human genome
D、comparing genome chunks of people from different continents
答案
D
解析
文章第六段第二句提到,为了(找到CNVs在整个人类基因中的分布),他们比较了270名欧洲、非洲或亚裔人的基因。[D]意为“比较来自不同大陆的人的基因”,与原文意思相符,故为答案。根据文章第七段首句,[A]是人与人之间有大约99.5%的相同基因这一结论的依据,而非本问题的依据,故排除;[B]意为“分析不同人的基因差异”,与原文意思相近,但未强调来自不同大陆的人,故排除。
转载请注明原文地址:https://kaotiyun.com/show/YdE7777K
0
大学英语六级
相关试题推荐
WhenToyotaMotorCorp.movedoneofitsdivisionsintoanenvironmentallyfriendly,or"green",buildinginTorrancethreeyear
Personalityistoalargeextentinherent—Atypeparentsusuallybringaboutatypeoffspring.Buttheenvironmentmustalsohav
Inthepasthundredyearsamillionpeoplehavediedinearthquakes,anothermillionhavebeenkilledby【B1】______andtornadoes
Inthepasthundredyearsamillionpeoplehavediedinearthquakes,anothermillionhavebeenkilledby【B1】______andtornadoes
TheU.S.governmentisaskingAmericanstoeatlessandexercisemoreinanefforttostemthecountry’sincreasingepidemicof
RecentlyasociologistfromtheUniversityofNewHampshire,MurrayStraus,presentedapapersuggestingthatcorporalpunishmen
A、Theboard.B、Themanager.C、Thechairman.D、Thechiefengineer.C男士在对话中提到董事长是公司法定代理人,故选C项。
A、Studyingwithapartner.B、Preparingsnacks.C、Playingcards.D、Learninghowtodesignbridges.C女士说:“我打算去学生娱乐中心打桥牌。”故答案为C。
A、Herdaughterisn’tinherclass.B、Sheisn’trelatedtothestudent.C、Shedoesn’tthinkthatshelookslikethestudent.D、Th
随机试题
中国现代文学史上第一部现代白话小说集是()
患者,男,32岁。因车祸右上肢受伤30分钟后被送入急诊室。体格检查:右肩活动受限,弹性固定,Dugas征阳性。右手指不能屈曲,拇指对掌不能,手指不能内收与外展,指间关节不能伸直。如果该患者Horner征阳性,则表示
可能患有胃癌的胃液是
有关装船准备和装船用具的费用以及装船的费用,一般应由()负担。
梁启超曾说,“我想中国历史上有意义的革命,……第三回就是我们今天所纪念的辛亥革命了。”关于辛亥革命的叙述正确的是()。
5,10,17,28,()
因长时间或大音量听耳机而导致听力受损的未成年人明显增多。有人推荐关注该问题的家长使用一种可以“自动关机”的耳机,这种耳机在持续运行合理时间后或者当音量达到一定限度时就会自动关机。其实,即使家长们采纳建议也于事无补,因为那些听耳机的未成年人都是自己采购耳机。
在文中的横线上填进哪组字最恰当?()。下边不含比喻修辞的一项是()。
抗日战争中,中国共产党之所以把游击战争提升到战略地位,是因为()
【S1】【S9】
最新回复
(
0
)