Patent ID: 8003767

Claim:
A method of generating a labelled primer extension product, comprising: enzymatically extending a primer-target hybrid in the presence of (i) a mixture of enzymatically-extendable nucleotides capable of supporting continuous primer extension and (ii) a terminator; wherein the primer or the terminator is labelled with a dye compound or an energy transfer compound; wherein the dye compound comprises a 3,7-diamino[8,9]benzophenoxazine structure and at least one sulfonate substituent; and wherein the energy transfer compound comprises: a donor compound which is linked by a linker to an acceptor compound, wherein the donor compound is capable of emitting excitation energy in response to absorption of light at a first wavelength, and the acceptor compound is capable of fluorescing at a second wavelength upon absorbing the excitation energy emitted by the donor compound; wherein one or both of the donor compound and the acceptor compound comprises the 3,7-diamnino-[8,9]benzophenoxazine structure and at least one sulfonate substituent.