During Illumina sequencing-by-synthesis, what causes the specific fluorescence emission during each cycle?
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Correct answer: Laser excitation of the fluorescent dye on each incorporated nucleotide
In Illumina sequencing, each nucleotide carries a reversible dye terminator unique to the base. After incorporation, a laser excites the fluorescent dye on the incorporated nucleotide, which emits light that identifies the base. Both the dye and the terminator are then chemically cleaved to restore the 3'-OH and allow the next synthesis cycle.
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