问题
单项选择题
在已知核苷酸序列的情况下，获得目的DNA最常用的方法是
A．化学合成法．
B．筛选基因组DNA文库
C．筛选cDNA文库
D．聚合酶链反应
答案
参考答案：D
解析：若已知核苷酸序列，可根据此序列设计引物，进行PCR(聚合酶链反应)扩增获得目的DNA。当然也可利用DNA合成仪通过化学合成法合成目的基因，但少用，因此最佳答案为D，而不是A。
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在已知核苷酸序列的情况下，获得目的DNA最常用的方法是
A．化学合成法．
B．筛选基因组DNA文库
C．筛选cDNA文库
D．聚合酶链反应
参考答案：D
解析：若已知核苷酸序列，可根据此序列设计引物，进行PCR(聚合酶链反应)扩增获得目的DNA。当然也可利用DNA合成仪通过化学合成法合成目的基因，但少用，因此最佳答案为D，而不是A。
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| Miss Zhao is one of the most popular teachers in the school. Yesterday she came into the 1 with a big smile on her face. She asid to her 2 that she was 3 to see they did well in the sports meeting. But 4 was not pleased to see the classroom last Saturday not as 5 as usual. She hoped they would chean the classroom every day.Wei Hua was on 6 yesterday. She said everyone was at 7 except Lin Tao. Then she told Miss Zhao about their 8 to the Great Wall last Sunday. Luckily the weather was 9 . The played games and had a picnic there. After Wei Hua 10 her talk, Miss Zhao began her lesson. | ||||
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