Recombinant kidney cell. Immunofluorescent light micrograph of a recombinant Green African monkey kidney cell expressing human DNA. Deoxyribonucleic acid (DNA) contains a cell's genetic instructions. When combined with DNA from another source it is known as recombinant DNA. This process of DNA combining is known as genetic engineering. Here, human DNA encoding for a tagged" version of a protein has been incorporated into the kidney cells. A fluorescent antibody (green) detects where the protein is located in the modified cell. Red cells are not making the human protein. The nuclei of all the cells are blue. Magnification: x624 at 6x4.5cm size."