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
Researchers have reconstructed an ancient human genome(基因组)for the first time, thanks to the discovery of a 4000-year-old strand
Researchers have reconstructed an ancient human genome(基因组)for the first time, thanks to the discovery of a 4000-year-old strand
admin
2013-09-07
53
问题
Researchers have reconstructed an ancient human genome(基因组)for the first time, thanks to the discovery of a 4000-year-old strand of hair in Greenland permafrost(永冻土). Experts say that similar techniques could be employed in many other ways, such as analyzing the DNA of South American mummies or crime victims.
The sample was taken from one of four strands of hair collected in Greenland by Danish archaeologists in the 1980s. The hairs are the only known human remains from the earliest people to settle in Greenland. A chance conversation alerted University of Copenhagen researcher Eske Willerslev, who was just back from two unsuccessful months in Greenland searching for human remains to test for DNA, to the sample, which had been stored at the National Museum of Denmark for more than 20 years.
Once they had the hairs in their possession, Willerslev and colleagues set about sequencing the sample. The team used dozens of sequencing machines to identify and map DNA fragments in the hair shafts, a process that took nearly 2 months. The data revealed more than 80% of the genome, coverage comparable to what can be done with a modern human genome.
"From the DNA, we can tell a lot about the individual," says Willerslev. "He had brown eyes, brown skin, a tendency to baldness, and dry earwax." The researchers have named him "Inuk," which means "man" or "human" in Greenlandic.
The genome also sheds light on where the man’s relatives came from. When the researchers compared his DNA with that collected from more than 40 Arctic and native North American populations, they concluded that the first people to settle in Greenland were related to groups now living in northeastern Siberia. The analysis also revealed that these first colonists were not the ancestors of the Inuit who live on the island now.
The researchers say that when it comes to ancient DNA, the Greenland sample may amount to low-hanging fruit. The hair had been preserved by cold for thousands of years, ideal conditions for recovering DNA. "Working with these young permafrost samples is worlds apart from working with older, non-permafrost samples," says Adrian Briggs, a researcher at the Max Planck Institute. He notes that the Greenland sample contains tens of thousands of times more DNA than typically found in Neandertal and early modern human samples from warmer environments.
Yet the discovery shows that with ever-cheaper genetic sequencing and faster computers, it is possible to recover a full nuclear DNA sequence from an ancient human, even when the genome is broken into tiny fragments. The nicest thing this paper shows is that the application of next-generation sequencing techniques is really going to expand what we can do with ancient DNA.
When Eske Willerslev decided to test the strands of hair for DNA, ______.
选项
A、he discovered the hair by chance
B、he failed in all the previous tests
C、the hair was found by him in Greenland permafrost
D、the hair was kept in National Museum of Denmark
答案
D
解析
原文该句提到的sample指的就是“头发”的样本,末尾的定语从句表明该头发样本当时收藏在丹麦国家博物馆中,因此,本题应选D。
转载请注明原文地址:https://kaotiyun.com/show/sc97777K
0
大学英语六级
相关试题推荐
A、Inagrocerystore.B、Inabank.C、Inabookstore.D、Inapostoffice.A综合推断题。对话中提到了商店会员卡、刷卡消费、给杂货打包等,再结合男士最后所说的,在美国的杂货店里确实得做
WiththeassassinationofPresidentMcKinley,TheodoreRoosevelt,notquite43,becametheyoungestPresidentintheNation’shi
A、Heisnotequaltothejob.B、Hedoesn’tthinkthejobischallengingenough.C、Heisnotwellpaidforhiswork.D、Hecannot
ItissaidthatinEnglanddeathispressing,inCanadainevitableandinCaliforniaoptional.Smallwonder.Americans’lifeexp
A、Visitanartmuseum.B、Seeanexhibitionabroad.C、Attendaweddingceremony.D、MakeavoyageoverthePacific.C对话中女士提到…mybe
America’sHotSchoolsCompetition’sintenseandtherearescoresofcolleges.Large,small,public,private,urban,rural—wh
America’sHotSchoolsCompetition’sintenseandtherearescoresofcolleges.Large,small,public,private,urban,rural—wh
A、Hehasfinishedthefirstdraft.B、Hehasjustgotstarted.C、Hehasfinishedthemainbody.D、Hehashandedthepaperin.B选项
Thatexperiencesinfluencesubsequentbehaviorisevidenceofanobviousbutneverthelessremarkableactivitycalledremembering
CrowsareprobablythemostfrequentlymetandeasilyidentifiablemembersofthenativefaunaoftheUnitedStates.Thegreatn
随机试题
教育规划系统性
牙尖交错位咬合接触异常导致的影响中不包括
单位工程施工组织设计中所涉及的技术组织措施应包括( )。
企业财务目标实现的稳健保证是()。
在股票数量一定的情况下,能够反映上市公司股东财富最大化目标实现程度的最佳指标是()。
胆汁质的神经过程的基本特性是()。(2004年12月三级真题)
关于遗忘的理论解释有()。
“法治”一词具有丰富的内涵,具体包括()。
我国对外开放的格局是()
Peopletendtocollectpossessions,sometimeswithoutbeingawareofdoingso.Indeed,theycanhavea【T1】______surprisewhenth
最新回复
(
0
)