Werner Arber's discovery of an enzyme that could cleave long strands of deoxyribonucleic acid (DNA) led to a revolution in genetics research, providing the foundation that led to techniques to separate and reassemble basic genetic material. Gene splicing, as it was called, proved invaluable for DNA sequencing and gene mapping, which focuses on genetic organization. Arber received the 1978 Nobel Prize in physiology or medicine for his research in this area, sharing the prize with American scientists Hamilton O. Smith and Daniel Nathans, who also played essential roles in the development of gene splicing. The most controversial outcome of this research, however, was the eventual manipulation of DNA structures by geneticists, first in test tubes and then in vivo, or within a living organism. Arber warned his fellow scientists that such genetic research should be used carefully and conducted studies and participated in symposia on how to prevent the...