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#Maxam-Gilbert

2 public questions tagged with this topic.

Sequencing

Which sequencing method avoids use of fluorescence?

Among common sequencing platforms, Ion Torrent uniquely performs label-free, optics-free detection by sensing proton release during polymerization. When nucleotide is incorporated, hydrogen ion acidifies microwell, detected by ion-sensitive field-effect transistor, eliminating costly lasers, filters and fluorescently labeled nucleotides entirely. Sanger sequencing traditionally uses fluorescent dyed terminators or radioactivity, Illumina uses four-color reversible terminators requiring optical scanning, while pyrosequencing uses luciferase bioluminescence but still optical detection. Therefore

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.

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Sequencing

The sequencing method with base-specific chemical cleavage is:

Maxam-Gilbert sequencing, also called chemical sequencing, identifies sequence not by polymerase extension but by base-specific chemical modification and cleavage of existing DNA. End-labeled DNA is divided into reactions treated with reagents preferential for G, A+G, C+T, C alone. For example, dimethyl sulfate methylates G, formic acid depurinates A and G, hydrazine attacks pyrimidines. Piperidine then cleaves backbone at modified sites, electrophoresis resolves resulting fragments. Pyrosequencing, Illumina SBS and Ion Torrent all synthesize DNA; only Maxam-Gilbert directly cleaves DNA at spe

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.

View Details