Question

To analyze the results of a DNA sequencing reaction, which type of gel should you prepare?

• A. nondenaturing polyacrylamide gel

• B. pulsed field gel

• C. denaturing polyacrylamide gel

• D. agarose gel

Answer 1

C. denaturing poly acrylamide gel

DNA Sequencing is the process of determining the nuclei acid sequence, the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of four bases: Adenine, guanine, cytosine and thymine.

DNA Sequencing may be used to determine the sequence of individual genes.

It is a key tool in forensic, medicine and anthropology.

Sanger Sequencing, Maxam-Gilbert (did epoxy) are the most used DNA Sequencing methods.

Sanger Sequencing : It is a method of DNA Sequencing based on the selective incorporation of chain terminating dideoxynucleotides by DNA polymerase during invitro DNA replication.

Process: The DNA sample is divided into four separate sequencing reaction containing all four deoxynucleotides and DNA polymerase. To each reaction is added only one of the four dideoxyonucleotides, while other added nucleotides are ordinary ones. The dideoxynucleotides concentration should be approximately 100 fold higher than that of the corresponding deoxynucleotide to allow enough fragments to be produced while still transcribing the complete sequence.

Following rounds of template DNA extension from the bound primer the resulting DNA fragments are heat denatured and separated by size using gel electrophoresis. This is performed by Poly acrylamide gel. The DNA bands may then be visualized by auto radiography.