DNA sequencing? Sanger method?

You have a sequence of bases that you want to read. This is your template.
You use a primer that always binds to the same region. This is your starting point
You then have premature termination of chain elongation by the polymerase because you attach a nucleotide that is not capable of binding to another nucleotide.
In each step you only have these special nucleotides being of one type only, I.e. Either G, T, C or A. Let's assume you just have G.
In the mix though, you have normal G nucleotides that can bind to other nucleotides as well. So whether it terminates at a G or not is purely up to luck.
Since your starting point of the polymerase is always the same, the shortest fragment is your starting "position", as this is the earliest possible place of G.
You repeat for all the nucleotides, and then you compare the sizes of the fragments, with the shortest one being the starting position.


copied and pasted from another post of mine here!