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By Frederick Sanger, S. Nicklen and Alan Coulson, printed as F. Sanger, S. Nicklen and A. R. Coulson. Their listed affiliation is the Medical Research Council Laboratory of Molecular Biology. Published in Proceedings of the National Academy of Sciences of the United States of America 74(12), 5463–5467, December 1977. The National Academy of Sciences is the publisher; PubMed Central hosts the archival record.
Inspected full-text mirror of the same article: nemates.org/uky/425/Sanger.PNAS.1977.v74.p5463-5467.pdf
Online text: pmc.ncbi.nlm.nih.gov/articles/PMC431765/
Cited passages: PMC bibliographic record and abstract; Full paper PDF text at nemates.org/uky/425/Sanger.PNAS.1977.v74.p5463-5467.pdf; p. 5464, Sequencing Procedure: restriction-fragment primers, heating/annealing, Klenow polymerase, radioactive dATP and chase-omission observation; p. 5464, Figure 1 caption: G/A/T/C lanes, araCTP C reaction, 12% acrylamide, 40 mA, 14 h; p. 5465, Figure 2 caption: ddCTP/all-dideoxy comparison; p. 5466, Results: weak fast T bands, unresolved long runs, comparison with provisional sequence and structure-dependent migration.
Sanger-Nicklen-Coulson sequencing experiment 2026-10-18
In 1977, Frederick Sanger, S. Nicklen and Alan Coulson tested chain termination on Phi X 174 DNA. They isolated restriction enzyme fragments as primers, heated them with template to for three minutes and annealed at for thirty minutes. Four extension mixtures used the Klenow fragment of DNA polymerase and radioactive dATP. Their Figure 1 used ddGTP, ddATP, ddTTP and araCTP, an alternative terminating substrate; Figure 2 used all four dideoxy types. This distinction matters when relating the original experiments to an all-ddNTP teaching model.[ref]
DNA sequencing with chain-terminating inhibitors by Frederick Sanger and others. Sanger, Nicklen and Coulson, DNA sequencing with chain-terminating inhibitors, PNAS 74 (1977), pp. 5463–5465, Sequencing Procedure and Figures 1–2
Figure 1 used a 12% acrylamide gel at for fourteen hours, read by autoradiography. Omitting the unlabeled dATP chase caused unwanted A stops across samples: a chemistry scientific control. Ordered bands supported local nucleotide sequences; comparisons could revise provisional assignments. Weak T bands, unresolved long runs and structure-dependent migration limited interpretation. The paper's observations are evidence from particular preparations, not a guarantee that every endpoint is resolved.[ref]
DNA sequencing with chain-terminating inhibitors by Frederick Sanger and others. Sanger, Nicklen and Coulson (1977), p. 5464, chase-omission observation and Figure 1 caption; p. 5466, Results: weak T bands, unresolved runs, sequence comparisons and structure-dependent migration