Molecular Biologist Discovered Transfer RNA

Mahlon Hoagland, 87, a biologist, teacher and artist who discovered a key step in the process by which the genetic code is translated into living tissue, died Sept. 18 at his home in Thetford, Vt., of kidney failure and lung problems.

The genetic code, which provides the instructions for the development of living things, is embodied in the celebrated DNA molecule. DNA is closely associated with RNA, a less-well-known molecule that plays a major role in translating genetic instructions into the proteins of living matter.

Dr. Hoagland discovered molecules known as transfer RNA. Transfer RNA locks onto amino acids, which are the building blocks of proteins. Then it carries the amino acids to the places where proteins are assembled. Dr. Hoagland also discovered how the amino acids are activated to take part in that process.

Guided by transfer RNA, amino acids fit one by one into spots indicated by still other types of RNA molecules. Those are known as messenger RNA, so named because they carry from DNA the messages of the genetic code.

The discovery of transfer RNA, made by Dr. Hoagland in 1953, with colleague Paul Zamecnik, forged a major link between biochemistry and molecular biology.

Dr. Hoagland was also known for a teaching style that fostered curiosity and clarified the complex. He was an avid sculptor whose chisels turned wood into waves and women, seagulls and children, and the helical DNA molecule.

He was a vivid writer, and the recounting of one of his discoveries included these words: "I still can clearly see the dark windows of the lab, smell the organic solvents, hear the buzzing of a defective fluorescent lamp in the next room."

Mahlon Bush Hoagland -- the first name was pronounced MAY-lin -- was born in Boston in 1921, the son of prominent physiologist Hudson Hoagland.

After receiving a bachelor's degree from Harvard College, he graduated from Harvard Medical School in 1948. Tuberculosis, which he contracted while treating a baby, weakened his body and shifted his goals from surgery to research.

He worked for years in laboratories at Massachusetts General Hospital, where he and Zamecnik discovered transfer RNA. He taught microbiology at Harvard Medical School and became head of the microbiology department at Dartmouth's medical school in New Hampshire. He later became head of the Worcester Foundation for Experimental Biology in Massachusetts.

He spent a year in the 1950s working at Cambridge University in England, with Francis Crick and James Watson, who discovered the structure of DNA.

His marriage to Elizabeth Stratton Hoagland ended in divorce. His second wife, Olley Hoagland, died in January. A daughter from his first marriage died. Survivors include three children from his first marriage, five stepchildren, four grandchildren and two great-grandchildren.

Daughter Robin Hoy said her father did not wish to spend his last days in a hospital. "He stopped eating and gradually reduced his intake of fluids," she said. "It was his intention not to live on in a compromised" state.