Practice Questions

TLS Online TPP Program

#Question id: 16134

You obtain 6 BACs (of known order, as shown below) and 7 STSs (of unknown order) that derive from a region of mouse chromosome 16 whose genomic sequence has not yet been finished.

By PCR (using 20-bp primers at either end of each STS), you test each of the 6 BACs for the presence (+) or absence (-) of each of the 7 STSs. You obtain the following results:

You determine the DNA sequences of PCR products obtained at STS5 using BACs B, C, D, E, and F as PCR templates. The DNA sequences of PCR products obtained using BACs B and C are identical, but they differ by several nucleotide substitutions from the DNA sequences of PCR products obtained using BACs E and F. Oddly, PCR product obtained using BAC D appears to be a mixture of two sequences – one corresponding to the BAC B/ BAC C sequence and the other corresponding to the BAC E/ BAC F sequence. Briefly account for these findings, and explain how a single PCR assay could amplify two different sequences.

#SCPH01 Biochemistry

PCR just amplifies RNA to which primers bind. One could imagine that the PCR primers could anneal to both sites and amplify both sites.
PCR just amplifies DNA to which primers bind. One could imagine that the PCR primers could anneal to one site and amplify only one site.
PCR just amplifies DNA to which primers bind, One could imagine that the PCR primers could anneal to both sites and amplify both sites.
PCR just amplifies protein to which primers bind. One could imagine that the PCR primers could anneal to both sites and amplify both sites.