Question

In automated DNA sequencing reaction by the Sanger method, which of the following is NOT a component of the reaction?

A) fluorescently-labeled deoxynucleotides

B) DNA polymerase

C) a DNA primer

D) the DNA to be sequenced

E) none of the above (i.e. all the above are required in the reaction)

Answer 1

option E)None of the above i.e All of the above is needed in automated DNA sequencing.DNA sequencing is the process of determining the sequence of nucleotide bases (As,Ts,Cs and Gs) in a piece of DNA . Automated DNA sequencing reaction by theSanger method utilizes dye to label the nucleotides instead of a radioactive isotope .The system automatically  identifies the nucleotide sequence and saves the information on the computer.In sanger sequencing ,the target DNA is copied many times making fragements of different lengths .Fluroscently labelled deoxynucleotide marks the end of the fragement and allow the sequence to be determined .The role of DNA polymerase is that they catalyze the biological reaction for deriving template sequence information .The role of DNA primer is that when the mixture is heated to denature the template DNA and cooled ,the DNA primer bind to the single stranded template and once the primer has bound ,the tempertaure is raised again ,allowing DNA polymerase to synthesize new DNA starting from the primer .And the DNA sample to be sequenced is combined in a tube with DNA primer,DNA polymerase and DNA nucleotides(dATP,dTTP,dGTP and dCTP).Thus ,all of the option is the component of the reaction.