Spare hearts. Conceptual computer artwork of spare hearts stored in jars, overlaid with the banding (pink & white) of a DNA autoradiogram. This may represent the growth of human tissue to produce material for transplant surgery to replace old or defective body parts. This technology may develop from work on stem cells or research into cloning. The image may also represent the transplantation of animal organs to humans (xenotransplantation). The banding of an autoradiogram shows the genetic code in a sample of DNA (deoxyribonucleic acid). DNA codes for the biochemical processes in all living organisms.