1试题与答案2016年课标理综卷(丙卷)第40题摘选:图1中的3个DNA片段上依次表示出了Eco RⅠ,BamHⅠ和Sau3AⅠ3种限制性内切酶的识别序列与切割位点,图2为某种表达载体示意图(载体上的EcoRⅠ和Sau3AⅠ的切点是唯一的)。根据基因工程的有关知识,回答下列问题:(2)若某人利用图2所示的表达载体获得了甲、乙、丙3种含有目的基因的重组子,如图3所示。这3种重组子中,不能在宿主细胞中表达目的基因产物的 1 Questions and Answers 2016 Lecturer, Volume I (Volume Two) Question 40: Three DNA fragments in Figure 1 show the recognition sequences of the three EcoRI, BamHI and Sau3AI restriction enzymes. The cleavage site, Figure 2 is a schematic representation of an expression vector (the cut points of the EcoRI and Sau3AI on the vector are unique). According to the knowledge of genetic engineering, answer the following questions: (2) If someone uses the expression vector shown in Figure 2 to obtain the three recombinants containing the target gene, as shown in Figure 3. In these three recombinants, the target gene product cannot be expressed in the host cell.