问题 单项选择题

由我国科学家精确绘制的水稻第四号染色体精确测序图今天发表在国际权威的英国《自然》杂志上。今天上午,科技部、中国科学院在上海宣布,我国科学家独立完成了“国际水稻基因组计划”第四号染色体精确测序任务,对这一国际计划的贡献率达到10%,这是我国迄今为止完成的最大基因组单条染色体的精确测序。

刊于《自然》杂志的论文《水稻基因组第四号染色体序列及分析》宣布,中国科学家采用克隆步移法完成了对水稻粳稻基因组第四号染色体全长序列的精确测定,拼接后总长为3500万碱基对,精确度为99.99%,覆盖了染色体全长序列98%的区域,达到国际公认的基因组测序图的标准。

科学家们在完成序列精确测定的同时,还做了大量的研究工作:对水稻第四号染色体所含基因进行预测分析,鉴定出4658个基因,并注释在染色体的准确位置上,为进一步鉴定这些基因的功能奠定了基础;完整地测定了水稻4号染色体的着丝粒序列,这是迄今首次完成的高等生物染色体着丝粒序列,为研究着丝粒的功能、染色体的稳定性和染色体的复制提供了结构基础,也为开发可转化的“人工水稻或植物染色体”提供了基础。以蓝天白云金色水稻为封面的本期《自然》杂志,同时也刊登了日本科学家对水稻第一号染色体的精确测序。

测序专家工作组组长、中科院国家基因研究中心的韩斌博士告诉记者,第四号染色体的测序工作于2001年4月启动,首先完成精细物理图,然后采用克隆步移法大规模测序,绘制基因组完成图。此外,研究人员还对另一个亚种籼稻品种广陆矮第四号染色体的序列也进行了测定,报道了水稻两个主要栽培稻种在基因组成、顺序及DNA序列水平上的一些异同,揭示两者之间一些亲缘和进化关系,这些数据为将来整个基因水平的比较提供了良好的示范。

韩斌博士还表示,目前世界上有一半以上的人口以水稻为主食。水稻基因组第四号染色体的序列分析结果和今后的功能基因组研究,可获得大量的水稻遗传信息和功能基因,为培育优良性状的水稻新品种打下良好基础。同时,此次测序成果,还将有助于了解小麦、玉米等其他重要粮食作物的遗传秘密,从而推动整个农作物基因组的研究。

根据文章内容,下列推断不正确的一项是()。

A.“国际水稻基因组计划”应是一项国际合作开发的计划,除中国科学家参加外,还有大量的外国科学家参与这一计划,中国只是承担了这一计划中的部分任务

B.“国际水稻基因组计划”的完成,可为培育优良性状的水稻新品种打下良好的基础

C.“国际水稻基因组计划”的完成可以部分地揭示小麦、玉米等其他重要粮食作物的遗传秘密

D.“国际水稻基因组计划”的完成,将可以推动整个农作物基因组的研究

答案

参考答案:C

解析:

原文是“还将有助于了解小麦、玉米等其他重要粮食作物的遗传秘密”,并非“可以部分地揭示”。

单项选择题
阅读理解

By 2012,the world may need to cope with as many as 50 million people who have fled their homeland,not for political or economic reasons but because the environment has been so badly changed that it cannot support life. The statement has been released by the United Nations to mark UN Disaster Reduction Day.

More people are made homeless by environmental disasters than by war,according to the research by the Red Cross. That reality is proved by the earthquake in Pakistan.

The widely publicized disaster has brought aid from the global community,according to Janos Bogardi,director of the United Nations University Institute for Environment and Human Security. “If we can move swiftly in and give them a new start where they are,then they may stay in the area. Otherwise,they become environmental refugees. Environmental­related migrations are most acute in Sub­Saharan Africa,but they also affect millions of people in Asia and India. Meanwhile,the United States is witnessing increased pressure from victims of mismanaged and worsening soil and water conditions in Mexico and Latin America.” he says. Janos Bogardi says these refugees suffer from the impact of gradual environmental change—global warming,sea level rise,air and water pollution and more intense storms,floods and droughts that degrade the land. This is a slow process,but unfortunately a process that is very difficult to go backwards once final damage is done.

Janos Bogardi says they are calling on the global community to recognize the serious situation of environmental refugees and to work together to lessen the impact of environmental disaster.

小题1:What may be the best title of the passage?

A.50 Million environmental refugees by 2010

B.Environmental refugees—an international problem

C.The cause of environmental disasters

D.Global aid pouring in小题2:Janos Bogardi’s attitude towards solving the problem is that of being ________.

A.constructive       

B.compromising

C.controversial

D.conservative小题3:According to the passage,the following are the main reasons for migrations except ________.

A.earthquake

B.water conditions

C.global community

D.worsening soil小题4:What is implied in the passage?

A.People all over the world have realized the impact of environmental disasters on refugees.

B.It is time for us to take some measures to solve the problem of environmental refugees.

C.The damaged soil can recover soon if people take care of it.

D.It is good for people to go elsewhere to make a living.