- You are interested in cloning a gene from the B.sanfranciscus genome, so you design PCR primers that shouldamplify a 1 kilobase pair (kbp) PCR product that contains the geneof interest.  After amplification, you will see if thePCR  was successful by loading the entire reaction ontoan agarose gel and performing electrophoresis to see if a productof the expected size was generated.  To visualize theDNA, you will stain the gel with a fluorescent dye called ethidiumbromide, which fluoresces when it binds to DNA. The sensitivity ofethidium-bromide-stained DNA is 10 nanograms (i.e. – theremust be at least 10 ng of DNA in the band in the gel to emit adetectable amount of light).
If your PCR reaction initiallycontained 30 B. sanfranciscus genomes, how many cycles ofPCR will required before there is a detectable amount of amplifiedproduct?  You can assume:  a) there is 1 copyof the gene per genome, b) the PCR occurs with perfect efficiencyand therefore the amount of product doubles after each cycle, and,c) that the molecular weight of a 1 kbp molecule of DNA is 6.5 x105Daltons. Express your answer in the number ofcomplete (not fractional) cycles and show your work.
