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
26
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.
By saying that the Greenland sample may be "low-hanging fruit"(Line 1-2, Para. 6), the researchers meant that _____.
选项
A、the sample was favorable for their test
B、the sample made the test more difficult
C、the sample brought about little benefits
D、the sample produced unexpected results
答案
A
解析
从第6段第2句中的ideal和最后一句中的tens of thousands of times more DNA等可知研究人员认为格陵兰岛的样本对他们的研究带来非常积极的帮助,因此,本题应选A。
转载请注明原文地址:https://kaotiyun.com/show/qYG7777K
0
大学英语六级
相关试题推荐
ItisnoteasytotalkabouttheroleofthemassmediainthisoverwhelminglysignificantphaseinEuropeanhistory.Historyan
A、Therearealtogetherthreedepartmentswhichprotectcustomersandworkers.B、Acompanywithpoorordangerousworkingconditi
A、Checkyournumberandcallagain.B、Telltheoperatorwhathashappened.C、Asktheoperatortoputyouthrough.D、Asktheoper
A、Theystaycloseduntilsummercomes.B、Theycaterchieflytotourists.C、Theyarebusyalltheyearround.D、Theyprovidequal
Overacenturyafteritended,theCivilWarremainsthefundamental【B1】_____inAmericanhistory.Itproducedalossoflife【B2】
A、Thepeoplewhohadsomedifficultiesintheirownculture.B、Thepeoplewhowerenotactiveandsuccessfulintheirowncultur
每年农历第一天开始,持续数周的春节在中国人看来是最宏大、最重要的年度节日,这就好比西方人眼中的圣诞节。为了庆祝家庭团圆,同时也表达了人们对即将到来的春天和百花盛开充满了新的希望,春节的庆祝活动丰富多彩。不同地区和不同民族的人庆祝春节的方式也不一样。除夕之夜
19世纪初,清王朝迅速衰败。英国在这一时期向中国输入大量鸦片(opium),清政府力图查禁鸦片。英国为保护鸦片贸易,于1840年对中国发动了侵略战争,清政府最后同英国政府签订了丧权辱国的《南京条约》(TreatyofNanking)。鸦片战争之后,英、
A、Playinaband.B、Workattheauction.C、Sellrefreshments.D、Collecttickets.C题目询问女士将做什么。C中sellrefreshments和原文的servefood相符
A、Invarioustents.B、Inuniversitybuildings.C、Inahospital.D、Inanauditorium.A原文出现的theuniversityathleticfield并没有在选项中出现
随机试题
患者,女,26岁,转身时突感右下腹疼痛不能直立。妇检:子宫正常大小,于右侧扪及拳头大小包块,形状规则,触痛明显,以子宫右角部为甚。诊断可能是()
Ⅰ型高脂蛋白血症患者,空腹血浆中升高的脂蛋白是()
口服雷公藤适用于
患者,男性,56岁,消化性溃疡病史10年,近3周来出现腹痛规律消失,且出现贫血、体重减轻。首先考虑的是
某10年期附息债券,面值为100元,市场价格为98元,一位基金经理用这个债券的当期收益率直接来估算其到期收益率,下列较为合理的解释是()。
企业采用支付手续费方式委托代销商品,委托方确认商品销售收入的时间是()。
计时工资制的不足主要包括()。
提出“要尽量多地要求一个人,也要尽可能地尊重一个人"观点的苏联教育家是()。
Whoisthespeakermostlikelyaddressing?
HasaRunawayGreenhouseEffectBegun?(Adapted)
最新回复
(
0
)