Question

Electronic Polymerase Chain Reaction (e-PCR) is a computational procedure that is used..

• A. to identify STS site within DNA sequences
• B. to identify EST site within DNA sequences
• C. to identify non-coding sequence site within DNA sequences
• D. to identify coding sequence site within DNA sequences

Hint:

Think of the "P-C-R" in e-PCR. It mimics the lab technique. PCR amplifies a specific site. In bioinformatics, that specific, unique, amplifiable site is called an STS. So, e-PCR finds STSs.

Answer 1

The Correct Option is A

Step 1: e-PCR Explained:
Electronic Polymerase Chain Reaction (e-PCR) is a bioinformatics tool that mimics lab PCR. In the lab, PCR amplifies a specific DNA segment using primers. e-PCR computationally does the same: it uses primer sequences to search a large DNA database (like a genome) for segments that the primers would amplify.
Step 2: e-PCR's Application:
e-PCR primarily aids genome mapping. A Sequence-Tagged Site (STS) is a short, unique DNA sequence (typically 200-500 base pairs) with known location and sequence, defined by PCR primers. e-PCR searches new DNA sequences (e.g., contigs) for known STSs. Finding an STS anchors the sequence to a chromosome map.
Other options:
EST (Expressed Sequence Tag) is a cDNA subsequence representing an expressed gene. While e-PCR could theoretically find them, its primary focus is STSs.
Identifying general coding or non-coding regions is too broad. e-PCR specifically searches for sites defined by a unique primer pair, i.e., an STS.
Step 3: Conclusion:
The main use of e-PCR is identifying Sequence-Tagged Sites (STSs) within larger DNA sequences, essential for genome mapping.