Insertion of unrelated DNA into the cells of an organism. There are many different reasons for gene transfer: for example, attempting to treat disease by supplying patients with therapeutic genes. There are also many possible ways to transfer genes. Most involve the use of a vector, such as a specially modified virus that can take the gene along when it enters the cell.

Dr. Donald Orlic, of the National Human Genome Research Institute's Genetics and Molecular Biology Branch, defines gene transfer.

Related terms: cell, deoxyribonucleic acid (DNA), DNA replication, mRNA, mutation, protein, vector.