Final answer:
Gene therapy is a cutting-edge biological technique focused on replacing defective genes with healthy ones to treat genetic diseases, often using viral vectors and advanced gene editing methods.
Step-by-step explanation:
Gene therapy is the experimental technique for repairing or replacing defective genes with the aim of curing heritable diseases. This technique employs various methods of genetic engineering to insert a healthy or non-mutated gene into cells that contain defective or mutant genes. The introduction of the good gene often utilizes a vector, typically a virus like an adenovirus, to deliver the DNA into the target cells. Advanced versions of gene therapy may even attempt to correct the gene mutation directly at its original location in the genome. Diseases such as severe combined immunodeficiency (SCID) have been treated using this innovative approach, though it remains mostly experimental at this stage. Gene editing also offers promise by enabling the alteration of DNA to remove disease-causing mutations, using strategies such as CRISPR-Cas9 technology.