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
There have been several claims to have cloned humans over the past few years. Most have been bogus. But the announcement made th
There have been several claims to have cloned humans over the past few years. Most have been bogus. But the announcement made th
admin
2014-09-19
76
问题
There have been several claims to have cloned humans over the past few years. Most have been bogus. But the announcement made this week by Woo Sur Hwang, of Seoul National University in South Korea, and his colleagues, is serious. It is the first to achieve the accolade of publication in a peer-reviewed scientific journal. Dr. Hwang’s work appears in Science.
The terminology of human development has become slippery over the past few years, in the hands of both "life-begins-at-conception" propagandists who want to stop this sort of research, and publicity-seeking scientists who have claimed more than they have really achieved. What Dr. Hwang and his team have created is not what developmental biologists would normally refer to as an embryo. But it is a genuine scientific advance. South Korea’s researchers have taken egg cells from volunteer women, removed the nuclei from those cells (which contain only half of the genetic complement required to make a human being, since the other half is provided by the sperm), and replaced each nucleus with one taken from one of the volunteer’s body cells (which contains a full genetic complement). Given a suitable chemical kick-start, such re-nucleated cells will begin dividing as though they were eggs that had been fertilised in the more traditional manner. Since they have all of the mother’s genes, they count as clones.
Then the team cultured the dividing eggs until they had formed structures called blastocysts, with a few dozen cells each. This is the significant advance. At this stage the structure, though still just a featureless ball of cells, has started to differentiate into the body’s three basic cell types (known as endoderm, mesoderm and ectoderm). The researchers were able to extract cells from some of their blastocysts, and grow tissues containing all three cell types.
These are so-called stem cells, which can be directed to form a wide variety of the specialised cells from which organs are built. That, not the creation of new human beings, is the stated reason for this sort of research, since specialised cells made this way might be used to replace the cells lost in diseases such as Parkinson’s and type-I diabetes. This process is known as therapeutic cloning.
No doubt Dr Hwang’s scientific success will sharpen the debate between those who see therapeutic cloning as a potential force for good, and those who see it as a step on the road to a cloned human being. The former have been queuing up to praise the scientist’s work. It is "a major medical milestone" that could help spur a "revolution", said Robert Lanza, a cloning expert.
But opponents of therapeutic cloning should not worry too much yet. The road from a blastocyst to a baby is a long and complex one. Nevertheless, the South Korean breakthrough make’s it more urgent than ever that legislation be passed differentiating clearly between therapeutic and reproductive cloning—permitting the former and prohibiting the latter.
The team’s claimed objective of its cloning research is to______.
选项
A、develop fertilized eggs with all mother’s genes
B、form body structures with all three basic cell types
C、obtain specialised cells from which organs are built
D、create new human beings
答案
C
解析
细节题。在第四段中,干细胞通过培养形成各种用于构建器官的特殊细胞(即C),是韩国研究人员宣称的进行研究的原因,而不是创造新人类(D)。A和B都与原文意思不一致。所以C是本题正确答案。
转载请注明原文地址:https://kaotiyun.com/show/AFWO777K
0
在职攻硕英语联考
相关试题推荐
Bearsmostlylivealone,exceptformothersandtheirbabies,andmalesandfemalesduringmatingseason.Bearsformtemporaryg
Didyourmumanddadgotouniversity,ordidtheyleaveschoolandgostraighttotheJobCentre?Theeducationalexperienceof
Tellingyourdoctoraboutallthemedicinesyoutakemayhelpavoidseriousdrug______.
WhatdidtheseveralhundredcollegestudentscompetetobuildrecentlyinWashington,DC?
Wemadeplansforavisit,but______difficultieswithcarpreventedit.
"Ismokeformyhealth,"Iproclaimedinanewspaperarticlepublishedin1979.SinceIamadoctor,thisadviceattractedamuse
Iftheuniversalityofimmersion-stylelanguageprograms,emergencytestprepclasses,tiredcollegekidsisanyindication,cra
Theupcomingmovie"TheScorpionsKing"isafiction,butrecentarcheologicalstudiesindicatetherereallywasaKingScorpion
Thelocalpeoplewerejoyfullysurprisedtofindthepricesofvegetablesnolonger______accordingtotheweather.
SpeakerA:Excuseme,couldyoutellmehowtogettotherailwaystation?SpeakerB:______
随机试题
三糖铁培养基与双糖铁培养基的区别在于加与不加
肝性脑病的所有体征中最具特征性的是()
适用于需对被并购企业进行绝对控股,同时要求并购企业实力强大,具有现金支付能力的资本运营方式是()。
在20世纪50年代至60年代美国研制洲际导弹的过程中,()应运而生。
根据我国《土地管理法》的有关规定,国家征收土地必须按法定程序进行,并根据被征收土地的(),按照法定标准给予征地补偿。
按照保障责任范围的差异,人身保险可以分为()
青山县卫计委《会议通知》各县食品加工行业:根据上级《关于对食品加工行业的卫生状况进行一次全面大检查的通知》精神,决定召开我县食品加工卫生会议,部署卫生检查工作。通知如下:一、会议时间:2016年3月10日至11日二
移送管辖:指人民法院在受理案件以后,发现本院对案件没有管辖权,因而将案件移交给有管辖权的人民法院管辖的制度。下列属于移送管辖的是()。
南京临时政府是一个资产阶级共和国性质的革命政权,表现在
设一设备在时间长度为t的时间内发生故障的次数N(t)~P(λt).求相继两次故障之间时间间隔T的概率分布;
最新回复
(
0
)