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
2016-08-29
23
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 modem 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 modem 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/YYG7777K
0
大学英语六级
相关试题推荐
DoctorsinBritainarewarningofanobesity(肥胖症)timebomb,whenchildrenwhoarealreadyoverweightgrowup.So,whatshould
A、EastAsia.B、WesternEurope.C、EasternEurope.D、WestAsia.C研究表明,在东欧,人们认为男人有更多的权利工作。
Overacenturyafteritended,theCivilWarremainsthefundamental【B1】_____inAmericanhistory.Itproducedalossoflife【B2】
Whywouldananimalkillitself?Itseemsastrangequestion,andyetitisonethathas【B1】______somepeopleforalongtime.T
Manynewmotherssufferfromextremetirednessevenfourmonthsaftergivingbirth,promptingexpertstowarntheyshouldnothu
Moderntechnologyhasputmenonthemoonanddecipheredthehumangenome.Butwhenitcomestobrewingupflutomakevaccines,
GeorgeWilliams,oneofScottsdale’slastremainingcowboys,hasbeenraisinghorsesandcattleonhis120acresfor20years.T
A、Hehaslongbeenfedupwithtraveling.B、Hepreferstostayhomefortheholiday.C、Heisgoingoutoftownforacoupleofd
A、Thewomanshouldgetherraincoat.B、Thewomanhaslistenedtotheweatherreport.C、Thewomanwillbecaughtintherain.D、T
A、SheiseagertobeacceptedintotheUniversity.B、SheiswaitingtoseeifshecouldgetthejobfromIBM.C、Sheisexpecting
随机试题
造成不良社会后果的政策僵化现象来源于过分注重_______。
下列不属于血吸虫性肝硬化超声特点的是
张护士负责配制消毒液,护士长要求使用次氯酸钠消毒液时应该
村的概念在法律上是指自治村,即设立村民委员会机构的农民集体,大致相当于计划经济时代的生产大队。村农民集体土地所有权属于()。
已知支承吊车梁的柱牛腿,如题图所示,宽度b=500mm,竖向力作用点至下柱边缘的水平距离a=50mm(已考虑安全偏差20mm),牛腿底面倾斜角α=45°,作用在牛腿顶部的按荷载效应标准组合计算的竖向力Fvk=715kN,竖向力的设计值Fv=915kN,吊车
公民身份的认定标准包括( )。
以下叙述错误的是()。
【2014.山东威海】桑代克提出的学习规律包括()。
证明推广的积分中值定理:设F(x)与G(x)都是区间[a,b]上的连续函数,且G(x)≥0,G(x)≠0,则至少存在一点ξ∈[a,b]使得
已知3个类A、B和C,其中类A由类B的一个实例和类C的1个或多个实例构成。能够正确表示类A、B和C之间关系的UML类图是(43)。
最新回复
(
0
)