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
2018-04-15
42
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://jikaoti.com/ti/8DxFFFFM
0
大学英语六级
相关试题推荐
A、Somepeoplerefusetopaytaxes.B、Therichpeoplepayhighertaxes.C、Everycitizenhasadutytopaytaxes.D、Thetaxesare
NurseHomeVisits:ABoostforLow-IncomeParents[A]NursehomevisitorTammyBallardhashadsomememorableexperiencesinclos
NurseHomeVisits:ABoostforLow-IncomeParents[A]NursehomevisitorTammyBallardhashadsomememorableexperiencesinclos
TheEnglishnationalcharacterisdualistic:Oneaspectisconservative,theotherextroverted(性格外向的).Thepubisafineexample
TheEnglishnationalcharacterisdualistic:Oneaspectisconservative,theotherextroverted(性格外向的).Thepubisafineexample
Britishdoctorsaretolaunchamajorclinicaltrialtoinvestigatewhetheracommonanti-depressiondrugcouldbeacheapande
A、Becauseheneedstobookaflight.B、Becauseheintendstotravelinthecountry.C、BecausehehopestoreturntotheU.S.A.
A、Todestroytreeroots.B、Todigestitsfood.C、Toprotectitsterritory.D、Tofinditsway.D由“Theknifefishproducesanelect
Inthepushtocuttheamountofcarbonwereleaseintotheatmosphere,solutionsusuallyfocusonhowtoreduceourpoweruseo
DoBritain’sEnergyFirmsServethePublicInterest?[A]Capitalismisthebestandworstofsystems.Lefttoitself,itwillemb
随机试题
绘画是原始艺术的主要样式之一,它的主题多是早期人类的【】
由Stewart—Hamilton关系式得到DSA的提示不包括
A.艾卷灸B.艾炷灸C.温和灸D.温针灸E.天灸白芥子灸属()
急性血源性骨髓炎早期局部穿刺的正确方法是
某企业为了扩大生产规模,拟购置一套新设备。企业管理部门提出A、B两个方案供选择。A方案是购置国产设备,全部购置成本为500万元,预计可使用5年。第1年现金净流量为100万元;第2~4年内,每年现金净流量均为180万元;第5年现金净流量为150万元;
背景资料:某市政H公司承接了一座多跨预应力箱梁桥。该桥为斜拉桥,索塔采用裸塔形式,跨河流段宽度为60m。桥梁基础采用钻孔灌注桩形式,双柱式桥墩,柱高为l8m,桥梁上部结构采用普通钢筋混凝土盖梁。上部结构0号块采用墩顶混凝土现浇施工,临时固结构造示
下面是已公布的2002年我国国际收支平衡表简表,请据此对2002年国际收支情况做一分析,在下列备选答案中选出正确答案。
关于行为治疗的步骤,下列说法中不正确的是()。
编写教材(教科书)的直接依据是()。
A.ImportanceofstayingintellectuallyactiveB.Effectsofagingonaperson’srecallabilityC.Short-termmemoryversuslong-te
最新回复
(
0
)