(b. July 25, 1920, London, Eng.—d. April 16, 1958, London)

The British scientist Rosalind Franklin was an unacknowl-edged contributor to the discovery of the molecular structure of deoxyribonucleic acid (DNA), a constituent of chromosomes that serves to encode genetic information.

Rosalind Elsie Franklin attended St. Paul’s Girls’ School before studying physical chemistry at Newnham College, Cambridge. After graduating in 1941, she received a fellow-ship to conduct research in physical chemistry at Cambridge.

But the advance of World War II changed her course of action: not only did she serve as a London air raid warden, but in 1942 she gave up her fellowship in order to work for the British Coal Utilisation Research Association, where she investigated the physical chemistry of carbon and coal for the war effort.

Nevertheless, she was able to use this research for her doctoral thesis, and in 1945 she received a doctorate from Cambridge. From 1947 to 1950 she worked with Jacques Méring at the State Chemical Laboratory in Paris, studying X-ray diffraction technology. That work led to her research on the structural changes caused by the formation of graphite in heated carbons—work that proved valuable for the coking industry.

In 1951 Franklin joined the Biophysical Laboratory at King’s College, London, as a research fellow. There she applied X-ray diffraction methods to the study of DNA. When she began her research at King’s College, very little was known about the chemical makeup or structure of DNA.

However, she soon discovered the density of DNA and, more important, established that the molecule existed in a helical conformation. Her work to make clearer X-ray patterns of DNA molecules laid the foundation for James Watson and Francis Crick to suggest in 1953 that the struc-ture of DNA is a double-helix polymer, a spiral consisting of two DNA strands wound around each other.

From 1953 to 1958 Franklin worked in the Crystallog-raphy Laboratory at Birkbeck College, London. While there she completed her work on coals and on DNA and began a project on the molecular structure of the tobacco mosaic virus.

She collaborated on studies showing that the ribonucleic acid (RNA) in that virus was embedded in its protein rather than in its central cavity and that this RNA was a single-strand helix, rather than the double helix found in the DNA of bacterial viruses and higher organisms.

Franklin’s involvement in cutting-edge DNA research was halted by her untimely death from cancer in 1958.