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You want to amplify an insert:

5'ATCAAGTCGTAGCATGCATGACGATCGACTAGCTAGCTAGCATGCTAGCATCGATCGATGCATGCTAGCTAGCATGCTACGATGCATGCATCGATCGATGCAAAAAAGGGCCTTACC3'.
You design primers based on the bolded regions. What are the primer pairs are correct?
A. 5'ATCAAGTCGTAGC3' 5'CCATTCCGGGAAA3'
B. 5'ATCAAGTCGTAGC3' 5'AAAGGGCCTTACC3'
C. 5'ATCAAGTCGTAGC3' 5'GGTAAGGCCCTTT3'

User Mattwarren
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1 Answer

2 votes

Final answer:

The correct primer pair is Option C, where both primers are complementary to their respective target regions and arranged in the 5' to 3' direction

Step-by-step explanation:

When designing primer pairs for DNA amplification, you must ensure that the primers are complementary to the target regions on opposite strands of the DNA to be amplified. For the given DNA sequence, provided primers must anneal to the 5' and 3' ends of the sense and antisense strands, respectively. The correct primer pairs are the ones that are complementary to the bolded regions and oriented in the 5' to 3' direction.

For option A, the forward primer is 5'ATCAAGTCGTAGC3' which matches the beginning of the sequence. However, the reverse primer is incorrect as it is not complementary to the bolded region at the 3' end of the given sequence.

For option B, the forward primer is still correct but the reverse primer, 5'AAAGGGCCTTACC3', while complementary, it does not read in the correct 5' to 3' direction. The correct reverse primer should read in the opposite direction to the DNA template strand.

Option C, the forward primer is also correct and the reverse primer 5'GGTAAGGCCCTTT3' is the reverse complement of the last bolded region on the DNA strand, reading in the correct direction. Hence, this primer pair can bind to the 5' end and the reverse complement of the 3’ end of the sequence, making this the correct choice.

User Dave Albert
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