首页
登录
职称英语
Nearly six years after the sequence of the human genome was sketched out, on
Nearly six years after the sequence of the human genome was sketched out, on
游客
2024-05-17
49
管理
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. [br] What does Matthew Hurles mean by "Everyone has a unique pattern" (Line 3, Para. 3)?
选项
A、Everyone has his own understanding of the pattern of DNA.
B、The differences in DNA can only influence people’s personality.
C、Different people may have large chunks of different genome.
D、One person’s string of DNA "letters" is 0. l%different from another’s.
答案
C
解析
文章第三段第二句提到,…人与人之间,非常多的基因有显著差异。[C]意为“不同的人基因会有巨大差别”,是原文的同义转述,故为答案。第二段第二句提到,这些差异…影响人的每个方面,从相貌、个性,到对疾病的敏感度,[B]的内容过于局限,故不选;[D]的含义过于绝对,与第二段首句中generally assumed不符,故排除。
转载请注明原文地址:http://tihaiku.com/zcyy/3601792.html
相关试题推荐
Nearlysixyearsafterthesequenceofthehumangenomewassketchedout,on
Nearlysixyearsafterthesequenceofthehumangenomewassketchedout,on
[originaltext]TeadrinkingwascommoninChinafornearlyonethousandyear
[originaltext]TeadrinkingwascommoninChinafornearlyonethousandyear
[originaltext]W:Excuseme,Sir.I’vebeenwaitingherefornearly20minutesj
IntheCaucasusregionoftheSovietUnion,nearly50outofevery100,000p
IntheCaucasusregionoftheSovietUnion,nearly50outofevery100,000p
IntheCaucasusregionoftheSovietUnion,nearly50outofevery100,000p
Nearlyallsurgicalstudentsstickthemselveswithneedlesand【C1】______ins
Nearlyallsurgicalstudentsstickthemselveswithneedlesand【C1】______ins
随机试题
Idecidednotto______Johnwhenhewasinsuchadesperateposition.A、vanishB、s
SolarPower
患者经治疗病情改善,水肿减轻,但出现烦躁,手足搐搦。最可能的原因是并发()
下列关于砌体抗压强度的说法哪一种不正确?()A.块体的抗压强度恒大于砌体的
A.疝环口位于腹壁下动脉内侧 B.疝环口位于腹壁下动脉外侧 C.疝内容物为坏
我国理财产品市场发展迅速,下列属于银行理财产品的有( )。A.货币型理财产品
关于世界第一个合作社“罗虚戴尔公平先锋社”,以下说法正确的有( )。 A.
以下关于幼儿园美术教育不正确的论述是( )。A.帮助幼儿学习、掌握一定的美术知
在多根K线的组合中,下列说法正确的是()。 A.最后一根K线的位置越低,越有
教师的职业道德主要表现为对教育事业的(),对学生的热爱和同事之间(
最新回复
(
0
)