Oliver Smithies (23 June 1925 – 10 January 2017) was a British-American geneticist and Nobel laureate,

He invented gel electrophoresis in 1955, which is now one of the basic techniques of biochemistry and molecular biology.

Much later, he worked on the technique of homologous recombination of transgenic DNA with genomic DNA. This is the most reliable method of altering animal genomes at present, and the technique behind gene targeting and knockout mice.

Martin Evans and Mario Capecchi were also working on this idea, and they were jointly awarded the Nobel Prize in Physiology or Medicine for 2007.