In the form of gene therapy used successfully for severe combined immunodeficiency syndrome, the genetic engineering of human cells is done by

Severe combined immunodeficiency syndrome is a rare genetic disorder that causes improper function and development of the T and B cells of the immune system. The gene therapy for this disorder is using a genetically engineered retrovirus to insert a healthy gene in the white blood cells of the patient. The white blood cells are then expressing the favourable enzyme that could correct the deficiency.

The infrared (ir) and the ultraviolet(uv) represent the two extremities of the visible spectrum (400-700nm). while ir represents electromagnetic radiation with wavelengths longer than those of visible light, uv represents wavelengths shorter than visible light