Concept 17 A gene is made of DNA.

In 1944, Oswald Avery and his colleagues, Colin MacLeod and Maclyn McCarty published their landmark paper on the transforming ability of DNA.

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Maclyn McCarty (1911-2005)

Oswald Theodore Avery (1877-1955)

Oswald Avery was born in 1877 in Halifax, Nova Scotia. His father was a Baptist minister, and when Oswald was ten, his father became the pastor at the Mariners' Temple in New York's Lower East Side. Avery's parents were strong, enterprising people. They managed quite well on a small pastoral salary in the midst of one of the most crowded and squalid areas of New York City. They received occasional monetary donations from John D. Rockefeller, the rich industrial, who was an active supporter of the Baptist Church.

As a young boy, Avery learned how to play the cornet and on Sunday afternoons would play to attract worshippers to the church. He was so good that he won a scholarship to the National Conservatory of Music. In 1893, Avery attended the Colgate Academy and later the Colgate University. He became the leader of the college band and acquired the nickname "Babe" because of his small stature.

Avery was a good student and graduated from Colgate with a B.A. Even though he took very few science courses at Colgate, after graduation Avery went to the College of Physicians and Surgeons to study medicine. At the turn of the century, the field of medicine was changing. Scientists were beginning to determine the nature and cause of disease. Though good with patients, Avery found medical research more intellectually satisfying.

In 1907, Avery accepted an associate directorship at Hoagland Laboratory in Brooklyn — the first privately endowed bacterial research laboratory in the United States. While at the Hoagland, Avery taught student nurses and earned another nickname: "Fess" for professor.

Avery worked on many strains of bacteria, applying different immunological and chemical methods. In 1913, Avery published a clinical study of the tuberculosis bacterium. This work attracted the attention of Dr. Rufus Cole, the director of the Rockefeller Institute Hospital, who offered Avery a job at the Rockefeller. Avery did his Pneumococcus work at the Rockefeller and stayed there until his retirement in 1948.

Avery was well-liked by his colleagues, even though he didn't spend much time socializing with them. He also traveled infrequently and rarely attended scientific conferences or meetings. The exception was his yearly summer vacation to Deer Island in Maine where he could indulge in one of his favorite pastimes, sailing.

After retirement, Avery moved to Nashville to be near his brother's family. Although he was offered an opportunity to continue his research career, Avery cultivated the lifestyle of the retired "country gentleman." He took long walks, gardened and spent time with his family. In 1954, he was diagnosed with liver cancer. Avery died the following year after a painful illness.

Although many scientists acknowledge the impact of Avery's work on the field of molecular biology, Oswald Avery did not win a Nobel Prize. The reason might be that Avery never publicly stated that a gene is made of DNA.

In his paper, Avery showed that DNA is the transforming principle. The implication is that transformation happens through the action of a gene on the DNA. How would you prove this?