The Oligonucleotide Primers Used in the Polymerase Chain Reaction Are $5 \text { '-ATGCTGAAACTTCTC } \cdots \text { GGGATGAAATCAGTTT-3' }$

Multiple Choice

The oligonucleotide primers used in the polymerase chain reaction are typically 20-30 nucleotides in length or longer; however, for purposes of this problem let's assume that 6 nucleotides is long enough. You wish to amplify the fragment shown below (the raised dots indicate several kilobases of DNA sequence not shown) and decide to design primers corresponding to the regions that are underlined. What primer sequences would you use? $5 \text { '-ATGCTGAAACTTCTC } \cdots \text { GGGATGAAATCAGTTT-3' }$
$3 \text { '-TACGACTTTGAAGAG } \cdots \text { ?????CTTTAGTCAAA-5' }$

A) 5'-TGAAAC-3' and 5'-AATCAG-3'
B) 5'-GTTTCA-3' and 5'-AATCAG-3'
C) 5'-GTTTCA-3' and 5'-CTGATT-3'
D) 5'-TGAAAC-3' and 5'-CTGATT-3'