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
4
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] 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://tihaiku.com/zcyy/3601794.html
相关试题推荐
Nearlysixyearsafterthesequenceofthehumangenomewassketchedout,on
Nearlysixyearsafterthesequenceofthehumangenomewassketchedout,on
Nearlysixyearsafterthesequenceofthehumangenomewassketchedout,on
[originaltext]TeadrinkingwascommoninChinafornearlyonethousandyear
[originaltext]TeadrinkingwascommoninChinafornearlyonethousandyear
IntheCaucasusregionoftheSovietUnion,nearly50outofevery100,000p
[originaltext]Nearlyonein11graduatesareunemployedsixmonthsafterle
Nearlyallsurgicalstudentsstickthemselveswithneedlesand【C1】______ins
Nearlyallsurgicalstudentsstickthemselveswithneedlesand【C1】______ins
Nearlyallsurgicalstudentsstickthemselveswithneedlesand【C1】______ins
随机试题
Mypatients,if______theopportunity,wouldfreelyconverseabouttheirproblem
A—WarningequipmentB—AccidentmanagementC—ProtectionmeasuresD—Riskasses
“21世纪人人健康”的三个总体目标是什么
个体身心发展的一般规律有个体身心发展的顺序性、_____、不平衡性、互补性和__
下列有关文学常识的表述错误的一项是()。 A.北宋诗文革新运动先驱范仲淹所倡
下列主体中,期货公司不得接受其委托为其进行期货交易的有( )A.某事业单位的工
某车间单一生产产品,车间生产面积2000平方米,单位面积有效工作时间为每日8小时
根据《标准设计施工总承包招标文件》,监理人更换总监理工程师时,应提前( )天通
对电气设施抗震设计,下列表述正确的是()。A.对单机容量为300MW的火力发电
企业需要支付的银行手续费,属于( )。A.生产费用 B.管理费用 C.财务费
最新回复
(
0
)