Which sequencing method produces light after nucleotide incorporation?
Pyrosequencing is a non-electrophoretic sequencing-by-synthesis platform that couples nucleotide incorporation to visible light production. Each cycle dispenses a single dNTP; if it is complementary to next template base, DNA polymerase incorporates it and releases inorganic pyrophosphate, PPi, stoichiometrically. ATP sulfurylase converts PPi to ATP, which drives firefly luciferase to oxidize luciferin emitting photons. Light intensity indicates incorporation and number of same bases in homopolymer runs. Sanger uses termination fluorescence, Ion Torrent measures pH change, and Maxam-Gilbert relies on chemical cleavage without light.
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.