首页
登录
职称英语
If you go down to the woods today, you may meet high-tech trees—genetically
If you go down to the woods today, you may meet high-tech trees—genetically
游客
2023-08-16
14
管理
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 half-way 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(幼苗).
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(基因修补)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. [br] Compared with genetic engineering of food crops, genetic engineering of trees _____.
选项
A、began much later
B、has developed more slowly
C、is less useful
D、was less controversial
答案
B
解析
本文并没有提到树木基因改良技术从什么时候开始,所以有可能树木的基因改良技术和别的基因改良技术在开始的时间上相差不大,但在所取得的成果方面却有很大的差别,因此,本题关键在于理解首段末句中的lag behind指的是程度上的落后,而非时间上的落后,故B正确。
转载请注明原文地址:https://tihaiku.com/zcyy/2932220.html
相关试题推荐
转基因食品(GeneticallyModifiedFood;GMF)是利用基因工程技术生产的食品。它具有产量高、营养丰富、抗病力强等优势,但也存在明
Ifyougodowntothewoodstoday,youmaymeethigh-techtrees—genetically
Ifyougodowntothewoodstoday,youmaymeethigh-techtrees—genetically
Ifyougodowntothewoodstoday,youmaymeethigh-techtrees—genetically
Ifyougodowntothewoodstoday,youmaymeethigh-techtrees—genetically
转基因食品(GeneticallyModifiedFood;GMF)是利用基因工程技术生产的食品。它具有产量高、营养丰富、抗病力强等优势,但也存在明
Ifyougodowntothewoodstoday,youmaymeethigh-techtrees—genetically
Ifyougodowntothewoodstoday,youmaymeethigh-techtrees—genetically
Ifyougodowntothewoodstoday,youmaymeethigh-techtrees—genetically
Ifyougodowntothewoodstoday,youmaymeethigh-techtrees—genetically
随机试题
Onetrulyremarkableachievementthatsetsushumansapartthe【M1】______re
IwasinnorthernKenya,whichissufferingthroughtheworstdroughttohi
ShouldChildrenUseInternetasEarlyasPossible?1.目前,中国孩子接触网络的年龄越来越小2.有人认为孩子
妥善处理好旅游接待过程中的问题与事故,是保证旅游服务质量,提高旅行社信誉的重要环
有支气管哮喘及机械性肠梗阻的患者应禁用A.异丙肾上腺素B.新斯的明C.山莨菪碱D
旅游产业发展模式的特征不包括( )。A.波动性 B.概括性 C.阶段性
临时反补贴措施实施的期限:自临时反补贴措施决定公告规定实施之日起不超过( )。A
总额法核算下,下列关于企业取得政府补助的会计处理表述中正确的有()。A.与
根据《质量管理体系要求》(GB/T19001—2016),包括组织的岗位、职责
女性,54岁,诊断为急性坏疽性阑尾炎伴弥漫性腹膜炎入院,行阑尾切除术。术后第5天
最新回复
(
0
)