Chapter 11, Problem 10P

Using PCR, you want to amplify an approximately 1 kb exon of the human autosomal gene encoding the enzyme phenylalanine hydroxylase from the genomic DNA of a patient suffering from the autosomal recessive condition phenylketonuria (PKU).

a.	Why might you wish to perform this PCR amplification in the first place, given that the sequence of the human genome has already been determined?
b.	Calculate the number of template molecules that are present if you set up a PCR reaction using 1 nanogram(1 × 10-9 grams) of chromosomal DNA from blood cells as the template. Assume that each haploid genome contains only a single gene for phenylalanine hydroxylase and that the molecular weight of a base pair is 660 grams per mole. The haploid human genome contains 3 × 109 base pairs.
c.	Calculate the number of PCR product molecules you will obtain if you perform 25 PCR cycles and the yield from each cycle is exactly twice that of the previous cycle. What would be the mass of these PCR products taken together?