Oliver Smithies researched physical chemistry, biochemistry, and genetics in England, Canada, and the United States during the twentieth and early twenty-first centuries and contributed to the study of gene function. During the 1950s, Smithies developed a technique to improve separating proteins based on their physical properties. Later, in the 1980s, Smithies utilized homologous recombination, a process that involves two similar pieces of deoxyribonucleic acid, or DNA, that exchange information, to target and manipulate specific genes. Smithies’s research on homologous recombination helped lead to the creation of the knockout mouse, a model organism that has genetic alterations to a single gene, to help researchers understand the function of genes in development. In 2007, Smithies received the Nobel Prize in Physiology or Medicine along with Sir Martin Evans and Mario Capecchi for work on introducing specific gene modifications in mice. Smithies’s scientific contributions toward developing the knockout mouse provided a basis for subsequent research studying the impact of different genes on human health.

Sir Martin John Evans researched developmental biology in the United Kingdom during the twentieth and early twenty-first centuries. He was among the first to isolate and grow embryonic stem cells in the lab. Embryonic stem cells have the ability to develop into many different cell types. Using those cells, Evans and his colleagues developed methods for introducing changes to the DNA of early mouse embryos. He found that when he introduced those modified embryos into foster mothers, the genetic alterations also appeared in subsequent generations. That finding helped him produce some of the first living mice with desired genetic changes, later dubbed knockout mice. In 2007, Evans received the Nobel Prize in Physiology or Medicine along with Mario Capecchi and Oliver Smithies for their work on introducing specific gene modifications in mice using embryonic stem cells. Evans’s scientific contributions have permitted scientists to better understand the roles of different genes in both embryological development and disease.