In Maxam-Gilbert sequencing, a band that is present in the lane from the tube treated with formic acid (G or A) but not the tube treated with dimethyl sulfate (G) is read as which of the following nucleotides?

Question

Quizplus · Accepted Answer

The band present in the lane from the tube treated with formic acid (G or A) but not the tube treated with dimethyl sulfate (G) indicates that the nucleotide is either G or A. In Maxam-Gilbert sequencing, formic acid cleaves the DNA strands at G and A residues, while dimethyl sulfate cleaves at G residues only. Therefore, if a band is present in the lane from the formic acid-treated tube but not the dimethyl sulfate-treated tube, it means that the nucleotide is an A, which is not cleaved by dimethyl sulfate.

In Maxam-Gilbert Sequencing, a Band That Is Present in the Lane