Practice question

In manual Sanger sequencing, termination products from synthesis reactions must be ordered by size to deduce sequence. Denaturing polyacrylamide gel electrophoresis provides single-nucleotide resolution due to its highly crosslinked matrix with small pore size, unlike agarose. Fragments migrate inversely to length; shorter fragments run faster and appear at bottom. By running four lanes or four colors in capillary, the ladder reveals base order. Polyacrylamide does not precipitate DNA, detect bases or primarily buffer pH. Its purpose is size separation with near single-base precision essential for accurate sequence reading.