A procedure that uses artificially synthesized primers about 18 bases long to bind to a unique DNA site. The primer is enzymatically extended by several hundred bases that are complementary to the target DNA. After sequencing the elongated primer, a sequence is selected near the far end to serve as a primer for the next “step” along the target DNA. A new 18 mers primer is then synthesized complementary to the far sequence from which the next round of extension can proceed.
Subjects: Genetics and Genomics.