Knockout Organism: Definition, History, and Further Reading
The term “knockout organism” refers to a living organism whose genetic material has been altered in order to disable or “knock out” a specific gene or set of genes. This allows for the study of the effects of the gene’s inactivation on the organism’s development, physiology, and/or behavior. Knockout organisms are used in a variety of scientific disciplines, including genetics, developmental biology, and neuroscience.
The concept of a “knockout organism” was first introduced in the late 1970s in the field of genetics. In 1978, Herbert Boyer and Stanley Cohen developed a technique known as recombinant DNA technology, which allowed for the modification of an organism’s existing genetic material. This technology enabled the insertion of foreign genes into an organism’s existing genome and the removal of existing genes. This technique was further refined in the early 1980s when the first “knockout mouse” was created by Mario R. Capecchi, Martin Evans, and Oliver Smithies. This mouse was created using the concept of homologous recombination, in which a gene of interest is selected and replaced with a modified version of the same gene. This modified gene is inactive and non-functional, thus disabling the gene’s associated function. Since the development of this technique, knockout organisms have become an invaluable tool in the study of gene function and have been used to study a wide range of topics, including disease mechanisms, gene regulation, and evolutionary biology.
Knockout organisms are an important tool in the study of gene function and have become increasingly important in the fields of genetics, developmental biology, and neuroscience. To better understand the role of knockout organisms in these fields, the following scientific journal articles are recommended:
Capecchi, M. R. (2005). Homing Endonuclease-Mediated Gene Targeting: A General Strategy for Manipulating the Mammalian Genome. Molecular and Cellular Biology, 25(16), 7233-7242. doi:10.1128/MCB.25.16.7233-7242.2005
Evans, M. J., & Kaufman, M. H. (1981). Establishment in culture of pluripotential cells from mouse embryos. Nature, 292(5819), 154-156. doi:10.1038/292154a0
Smithies, O., Gregg, R. G., Boggs, S. S., Koralewski, M. A., & Kucherlapati, R. S. (1985). Insertion of DNA Sequences into the Human Genomic DNA. Proceedings of the National Academy of Sciences, 82(11), 5148-5152. doi:10.1073/pnas.82.11.5148
Somerville, R. C., & Schimenti, K. J. (1999). Knockout Mice: Teaching an Old Dog New Tricks. Genetics, 151(3), 889-901. doi:10.1534/genetics.151.3.889