A Sanger dideoxy approach was used to determine the sequence

A Sanger dideoxy approach was used to determine the sequence of a gene X. Results of the DNA sequencing were shown below on the gel. Samples were loaded on the top of the gel. The positive electrode is located at the bottom of the gel. What is the sequence of the template DNA that was used to generate the Sanger dideoxy sequencing gel shown below? Be sure to indicate the 5’ and 3’ ends. Note that the letter above each lane indicates the dideoxynucleotide that was present in the tube whose reaction was loaded into that lane.

Solution

The sequence read from the gel is:

5\' TGAACGCATGCT 3\'

So the template strand is:

3\' ACTTGCGTACGA 5\'