US Patent 7244567 Double ended sequencing

This invention relates to methods of sequencing DNA. More specifically, this invention relates to methods of sequencing both the sense and antisense strands of DNA through the use of blocked and unblocked sequencing primers. In brief, these methods include the steps of annealing an unblocked primer to a first strand of nucleic acid; annealing a second blocked primer to a second strand of nucleic acid; elongating the nucleic acid along the first strand with a polymerase; terminating the first sequencing primer; deblocking the second primer; and elongating the nucleic acid along the second strand.