首页
登录
职称英语
Researchers have reconstructed an ancient human genome(基因组)for the first tim
Researchers have reconstructed an ancient human genome(基因组)for the first tim
游客
2023-08-25
49
管理
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. [br] 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://tihaiku.com/zcyy/2955174.html
相关试题推荐
Researchershavereconstructedanancienthumangenome(基因组)forthefirsttim
Researchershavereconstructedanancienthumangenome(基因组)forthefirsttim
Researchershavereconstructedanancienthumangenome(基因组)forthefirsttim
AstudyledbyresearchersattheUniversityofPennsylvaniaindicatesthat
Researchershavefoundthatpeople’smentalabilitiespeakat22beforebegi
Researchershavefoundthatpeople’smentalabilitiespeakat22beforebegi
Researchershavefoundthatpeople’smentalabilitiespeakat22beforebegi
Researchershavefoundthatpeople’smentalabilitiespeakat22beforebegi
Researchershavefoundthatpeople’smentalabilitiespeakat22beforebegi
Researchershavefoundthatpeople’smentalabilitiespeakat22beforebegi
随机试题
Therearemanywaysofdealingwithoffendersthatdonotinvolvethepayment
[A]Withhisdrywitandimpeccable(无瑕疵的)style,JamesBondhasbeendefyingdeath
要求参与项目实施与管理人员树立质量第一,用户第一的观点的保证体系为( )。A.思
污水厂中预处理单元和二沉池的设计流量应按下列哪项确定?()A.平均日流量
关于Tc细胞识别抗原,说法正确的是A.受MHcⅠ类分子限制 B.受MHCⅡ类分
(2020年真题)关于竞业禁止条款,以下表述错误的是()A.竞业禁止条款的
B左边5个图的外壳都是一个常用的规则图形,且曲线图与折线图交替出现,所以第6个图形也应是一个常用的规则的折线图形,选B。
某单位计划在第5年末购置一台价格为1000万元的大型设备,若存款年利率为4%,从
有关真核DNA的复制,正确的是A.仅有一个复制体形成,因为只有单一复制起始点
投资项目决策分析与评价的基本要求包括贯彻落实科学发展观、资料数据准确可靠和()
最新回复
(
0
)