Gene knockout is a research technique used to study the function of a specific gene by deactivating or "knocking out" its expression in an organism. This can be achieved through a variety of methods, such as using CRISPR/Cas9 technology to target and modify the gene of interest. By comparing the phenotype of the genetically modified organism to a normal organism, researchers can determine the role of the gene in specific biological processes or diseases. Gene knockout studies are essential for understanding gene function, genetic disorders, and potential therapeutic targets.