A type of virus containing RNA as its genetic material. The RNA of the virus is translated into DNA, which inserts itself into an infected cell's own DNA. Retroviruses can cause many diseases, including some cancers and AIDS. Scientists, however, can also genetically modify benign retroviruses and use them in gene therapy to correct abnormal cells by introducing normal genes into them.

Dr. Richard Morgan, of the National Human Genome Research Institute's Clinical Gene Therapy Branch, defines retrovirus.

Related terms: cancer, cell, deoxyribonucleic acid (DNA), gene, gene therapy, genome, human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), protein, ribonucleic acid (RNA).