Virtual terminator nucleotides for next-generation DNA sequencing

Abstract
Nucleotide analogs modified with a free 3′ hydroxyl, maintaining the interactions at the polymerase active site, and a cleavable linker, attaching a fluorescent dye and an inhibitor, are efficient at reading homopolymer runs in a single-molecule sequencing reaction. We synthesized reversible terminators with tethered inhibitors for next-generation sequencing. These were efficiently incorporated with high fidelity while preventing incorporation of additional nucleotides, and we used them to sequence canine bacterial artificial chromosomes in a single-molecule system that provided even coverage for over 99% of the region sequenced. This single-molecule approach generated high-quality sequence data without the need for target amplification and thus avoided concomitant biases.