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
考研
If you go down to the woods today, you may meet high-tech trees—genetically modified to speed their growth or improve the qualit
If you go down to the woods today, you may meet high-tech trees—genetically modified to speed their growth or improve the qualit
admin
2015-07-13
64
问题
If you go down to the woods today, you may meet high-tech trees—genetically modified to speed their growth or improve the quality of their wood. Genetically-engineered food crops have become increasingly common, albeit controversial, over the past ten years. But genetic engineering of trees has lagged behind.
Part of the reason is technical. Understanding, and then altering, the genes of a big pine tree are more complex than creating a better tomato. While tomatoes sprout happily, and rapidly, in the laboratory, growing a whole tree from a single, genetically altered cell in a test tube is a tricky process that takes years, not months. Moreover, little is known about tree genes. Some trees, such as pine trees, have a lot of DNA—roughly ten times as much as human. And, whereas the Human Genome Project is more than halfway through its task of isolating and sequencing the estimated 100,000 genes in human cells, similar efforts to analyze tree genes are still just saplings.
Given the large number of tree genes and the little that is known about them, tree engineers are starting with a search for genetic "markers". The first step is to isolate DNA from trees with desirable properties such as insect resistance. The next step is to find stretches of DNA that show the presence of a particular gene. Then, when you mate two trees with different desirable properties, it is simple to check which offspring contain them all by looking for the genetic markers. Henry Amerson, at North Carolina State University, is using genetic markers to breed fungal resistance into southern pines. Billions of these are grown across America for pulp and paper, and outbreaks of disease are expensive. But not all individual trees are susceptible. Dr. Amerson’s group has found markers that distinguish fungus-resistant stock from disease-prone trees. Using traditional breeding techniques, they are introducing the resistance genes into pines on test sites in America.
Using genetic markers speeds up old-fashioned breeding methods because you no longer have to wait for the tree to grow up to see if it has the desired traits. But it is more a sophisticated form of selective breeding. Now, however, interest in genetic tinkering is also gaining ground. To this end, Dr. Amerson and his colleagues are taking part in the Pine Gene Discovery Project, an initiative to identify and sequence the 50,000-odd genes in the pine tree’s genome. Knowing which gene does what should make it easier to know what to alter.
What is the primary objective of carrying out the Pine Gene Discovery Project?
选项
A、To speed up old-fashioned breeding methods.
B、To identify all the genes in the pine tree’s genome.
C、To find out what desired traits the pine trees have.
D、To make it easier to know which gene needs altering.
答案
B
解析
事实细节题。根据题干中的专有名词Pine Gene Discovery Project定位至最后一段倒数第二句。该句中的all initiative…是the Pine Gene Discovery Project的同位语,表明开展该计划的目的,因此B项为本题答案。
转载请注明原文地址:https://kaotiyun.com/show/J074777K
0
考研英语一
相关试题推荐
Educationisoneofthekeywordsofourtime.Aman,withoutaneducation,manyofusbelieve,isanunfortunatevictimofunfo
[A]Whattodoasastudent?[B]Variousdefinitionsofplagiarism.[C]Ideasshouldalwaysbesourced.[D]Ignorancecanbeforgive
TherearemoredifferencesbetweentheUnitedStatesandJapanthanconflictingvaluesduringWorldWarII.Culturalandsocieta
Becauseagricultureissoimportanttoanation’swell-being,governmentshavealwaysbeenconcernedwithit.Forexample,theU
Howmuchdoesaplaneticketreallycost?Justadecadeago,whenmostairfaresincludedacheckedbagandtheabilitytoreserv
Languagemeansthatwehaveself-consciousness,whichmakesusauniquespeciesabletocontrolourselvesandourenvironmentsi
Aschildhood-obesityratesskyrocket,doctorsareseeinganalarmingriseinacostlydiseaseonceunheardofinchildren;type
Cancerisataleoftwosetsofgeneticcode,yourownandyourtumor’s—andtracingtheuniqueareasofdamagemakesforawayt
Whenourchildrenareborn,westudytheireveryeyelashandmarvelattheperfectionoftheirtoes,andinnotimebecomeexper
Youaregoingtoreadalistofheadingsandatextabouttherelationshipbetweenwomenandbusiness.Choosethemostsuitable
随机试题
治疗瘀血所致的胁痛,可用
复温法是治疗小儿五硬证的重要措施之一,下列哪项不是复温的合理方法
建筑混凝土灌注桩采用钻芯法,当钻芯孔为一个时,宜在距中心()的位置开孔。
我国增值基本税率为17%,但对于一些关系到国计民生的重要物资,增值税税率较低,为13%,在下列选项中,增值税不是13%的是()。
某社会工作服务中心想为某社区老人提供服务,并向区民政局申请经费资助。区民政局很支持这一想法,要求中心准备材料,并写明服务的必要性、可行性、目标、专业方法、服务成效以及经费预算等内容。这份材料被称为()
下列描述正确的是()
武警对于海关工作给予过很多帮助,因而领导让你组织一次慰问武警的活动,你怎么组织?
从行文方向来看,()既可以下行,也可以上行和平行。
下列属于精神障碍的有()。
CanAddedCalciumHelpOlderBones?NewZealandresearcherssayguidelinesadvisingseniorstoconsumeatleast1,000to1,2
最新回复
(
0
)