Editing Genomics (section)

=== DNA-sequencing technology developed ===
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| image1 = Frederick Sanger2.jpg
| caption1 = Frederick Sanger
| image2 = WalterGilbert2.jpg
| caption2 = Walter Gilbert
| footer = [[Frederick Sanger]] and [[Walter Gilbert]] shared half of the 1980 Nobel Prize in Chemistry for Independently developing methods for the sequencing of DNA.
}}

In addition to his seminal work on the amino acid sequence of insulin, [[Frederick Sanger]] and his colleagues played a key role in the development of DNA sequencing techniques that enabled the establishment of comprehensive genome sequencing projects.<ref name = "Pevsner_2009"/> In 1975, he and Alan Coulson published a sequencing procedure using DNA polymerase with radiolabelled nucleotides that he called the ''Plus and Minus technique''.<ref name = "Tamarin_2004"/><ref name = "Sanger_1980"/> This involved two closely related methods that generated short oligonucleotides with defined 3' termini. These could be fractionated by [[electrophoresis]] on a [[polyacrylamide]] gel (called polyacrylamide gel electrophoresis) and visualised using autoradiography. The procedure could sequence up to 80 nucleotides in one go and was a big improvement, but was still very laborious.  Nevertheless, in 1977 his group was able to sequence most of the 5,386 nucleotides of the single-stranded [[bacteriophage]] [[Phi X 174|φX174]], completing the first fully sequenced DNA-based genome.<ref name = "Sanger_1977"/> The refinement of the ''Plus and Minus'' method resulted in the chain-termination, or [[Sanger method]] (see [[#Shotgun sequencing|below]]), which formed the basis of the techniques of DNA sequencing, genome mapping, data storage, and bioinformatic analysis most widely used in the following quarter-century of research.<ref name = "Kaiser_2003"/><ref name = "Sanger_1977a"/> In the same year [[Walter Gilbert]] and [[Allan Maxam]] of [[Harvard University]] independently developed the [[Maxam-Gilbert sequencing|Maxam-Gilbert]] method (also known as the ''chemical method'') of DNA sequencing, involving the preferential cleavage of DNA at known bases, a less efficient method.<ref name = "Gilbert_1977"/><ref name = "Darden_2010"/> For their groundbreaking work in the sequencing of nucleic acids, Gilbert and Sanger shared half the 1980 [[Nobel Prize]] in chemistry with [[Paul Berg]] ([[recombinant DNA]]).