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
Wiping away doubts that Dolly the sheep clone was a fluke, University of Hawaii researchers announced they’ve been cloning mice
Wiping away doubts that Dolly the sheep clone was a fluke, University of Hawaii researchers announced they’ve been cloning mice
admin
2013-01-12
35
问题
Wiping away doubts that Dolly the sheep clone was a fluke, University of Hawaii researchers announced they’ve been cloning mice for months, creating a flock of more than 50 duplicate rodents along the way. 71.
The success of the Hawaii group transforms adult cloning from a scientific novelty to a well-defined procedure likely to be .reproduced in labs around the world. The mass production of carbon copy mice, in turn, now allows researchers to test variations of the cloning techniques to see what works best.
Cloning the genetically engineered mice used in medical studies should also be cheaper than current breeding methods.
The Hawaii researchers use essentially the same recipe used to make Dolly: Take an egg. Scoop out the nucleus, which contains the DNA genetic information, and discard. Take a cell of the animal you wish to clone and insert its DNA into the egg. Add chemicals to tell the egg to start developing into an embryo. Incubate the embryo in a test tube for a few days, and then implant it into a foster mother. Wait for the foster mother to give birth to the clone. 72.
Where they modified the recipe was the method for moving the DNA from the animal-to-be-cloned into the egg. Most researchers had thought that mice would be particularly difficult to clone, because the DNA in mice embryos switches on very early, possibly as soon as the egg splits into the two-cell stage.
Because adult cells have specific, specialized functions, most of the unused DNA has been turned off. Scientists had thought that the implanted DNA would not have enough time to "repro- gram" itself back to the embryonic, unspecialized state. Thus, most cloning research has focused on animals where the DNA switches on later, allowing more time for the reprogramming. 73.
In cows, for example, the DNA switch-on occurs when the embryo reaches the eight-cell stage. No one is sure how the ttawaii group got the mouse DNA to reprogram itself more quickly, but some have the suspicion that getting rid of the outer part of the adult cell speeds the process.
In addition to various genetic tests, the researchers used a simple color scheme to verify that the DNA of the babies was not contaminated by either the egg donor or the foster mother. The eggs came from black mice, while the foster mothers were all white mice. The baby mice all came out coffee-colored, the color of their identical DNA mother. The researchers have licensed their technology to venture capital company ProBio America Inc. , based in Honolulu. "This technique we are expanding into the large commercial animals, such as cows and sheep, where much of our business is intended to be," says ProBio’s Cameron Reynolds.
选项
答案
例如,牛的胚胎在发育成8个细胞的阶段时DNA才山现转换。没有人知道夏威夷的研究人员是如何使老鼠的DNA更快地重编自己的程序的,但有些人怀疑是剔除成年细胞的外层加快了进程。
解析
转载请注明原文地址:https://jikaoti.com/ti/koHYFFFM
0
考博英语
相关试题推荐
Inasmuchasayeardoesnotelapsewithoutacertainnumberofvillagersfallingvictimtotheferocityoftiger,itsroaris__
Time,asweknowit,isaveryrecentinvention.Themoderntime-senseishardlyolderthantheUnitedStates.Itisaby-produc
Writeanapplicationletter.Youshouldwriteabout100words,andbaseyourcompositionontheoutlinebelow.Supposeyoua
AttackinganincreasinglypopularInternetbusinesspractice,aconsumerwatchdoggroupMondayfiledacomplaintwiththeFedera
Severalguestswerewailingonthe______forthefrontdoortoopen.
ItisincongruousthatthenumberofBritishinstitutionsofferingMBAcoursesshouldhavegrownby254percentduringaperiod
Totheirgreatsurprise,theyfoundthefloodwaterhaddamagedthebuilding’sfoundation.
Americanwomenexperienceagreat【1】oflifestyles.A"typical"Americanwomanmaybesingle.Shemayalsobedivorcedormarried
AmitaiEtzioniisnotsurprisedbythelatestheadingsaboutschemingcorporatecrooks(骗子).AsavisitingprofessorattheHarva
随机试题
设随机变量X的概率密度函数为(Ⅰ)求常数A,a;(Ⅱ)求E(Y).
混合型政治文化
采用慢速维持荷载法对某直径为1.2m、桩长为20m的桥梁桩基进行竖向静载试验,已知桥位处地基土为坚硬黏质土,请回答以下问题。当出现下列()情形之一时,应终止加载。
纳税人如果不能按转让房地产项目计算分摊利息支出,那么其允许扣除的房地产开发费用应为取得土地使用权所支付的金额加开发成本之和的( )。
甲公司是一家国有独资公司,以下表述正确的是()。
下列属于统计分析报告的特点的有()。
被称为“中国工艺美术三长”的是()。
土地增值税,指对转让房地产,即转让国有土地使用权和地上建筑物及其附着物并取得收入的单位或个人征收的税。土地增值税按照1994年1月1日起施行的《土地增值税暂行条例》征收。下列情况应征收土地增值税的是( )。
Airpollutionkilledaboutsevenmillionpeoplelastyear,makingittheworld’ssinglebiggestenvironmentalhealthrisk,theW
ThefirstfarmanimalJackever【51】fromastockyardwasalamb【52】Hida.aamSanctuary,180acresofveganheavenintheFingerL
最新回复
(
0
)