What term refers to the deliberate insertion, alteration, or deletion of genes in cells for therapeutic purposes?

The term that refers specifically to the deliberate insertion, alteration, or deletion of genes in cells for therapeutic purposes is gene therapy. This process involves manipulating an individual’s genes to treat or prevent disease, particularly genetic disorders and some types of cancer.

Gene therapy aims to correct faulty genes or provide beneficial ones to help treat medical conditions. It can involve various techniques, such as using viruses as vectors to deliver new or modified genes into the patient's cells, thereby enabling the cells to produce proteins or enzymes that they previously could not produce effectively.

In contrast, genetic engineering broadly encompasses a range of techniques, including altering the genetic makeup of organisms in general, which may not always align with therapeutic purposes. Gene expression refers to the process by which the information from a gene is used to synthesize functional gene products like proteins, while cloning ensures replication of genetic material or entire organisms but does not inherently involve therapeutic gene manipulation.