What sequencing method did the Human Genome Project primarily use?

The Human Genome Project primarily used Sanger sequencing. Developed by Frederick Sanger and colleagues in the 1970s, this chain-termination method reads DNA by creating fragments that end at each possible nucleotide, allowing the sequence to be reconstructed.

The project did not sequence the entire three-billion-base-pair genome in one piece. Researchers first mapped chromosomes, broke DNA into manageable fragments, and used a hierarchical shotgun strategy to sequence overlapping pieces. Automated Sanger machines then produced the sequence data, while computers assembled those overlapping fragments into larger stretches.

Sanger sequencing was slower and more expensive than modern next-generation methods, but it offered the accuracy needed for the first reference genome. Nanopore sequencing and pyrosequencing were not the project’s primary technologies. Next-generation sequencing became important later, enabling much faster and cheaper genome analysis for many individuals.