申論題

10. Eric Wang generated a plasmid that contains the entire coding region of human hypoxanthine guanine phosphoribosyltransferase (HGPRT) cDNA. The plasmid was termed pCMV/HGPRT-cDNA as shown in Fig. 1. Eric Wang wanted to identify the pCMV/HGPRT-cDNA from 4 plasmids. In the first experiment, the 4 plasmids were analyzed by PCR using primers that are labelled as in Fig 1, and electrophoresis was performed on the PCR product as shown in Fig. 2.   ln the second experiment, the same 4 plasmids were digested with Nco I, and the digests were separated by gel electrophoresis as shown in Fig. 3. Questions :

g. What is a useful alternative method to determine which plasmids contain the HGPRT-cDNA? (2%)