Oswald Avery - Breakthrough Discovery

Breakthrough Discovery

For many years, genetic information was thought to be contained in cell protein. Continuing the research done by Frederick Griffith in 1927, Avery worked with MacLeod and McCarty on the mystery of inheritance. He had received emeritus status from the Rockefeller Institute in 1943, but continued working for five years, proving that not all breakthrough discoveries are achieved by younger people (by this time he was in his late sixties). Techniques were available to remove various organic compounds from bacteria, and if the remaining organic compounds were still able to cause R strain bacteria to transform then the substances removed could not be the carrier of genes. S strain bacteria first had the large cellular structures removed. Then they were treated with protease enzymes, which removed the proteins from the cells before the remainder was placed with R strain bacteria. The R strain bacteria transformed, meaning that proteins didn't carry the genes causing the disease. Then the remnants of the R strain bacteria were treated with a deoxyribonuclease enzyme which removed the DNA. After this treatment, the R strain bacteria no longer transformed. This indicated that DNA was the carrier of genes in cells.

Alfred Hershey and Martha Chase furthered Avery's research in 1952 with the Hershey-Chase experiment. These experiments paved the way for Watson and Crick's discovery of the helical structure of DNA, and thus the birth of modern genetics and molecular biology. Of this event, Avery wrote in a letter to his youngest brother Roy, a bacteriologist at the Vanderbilt School of Medicine: "It's lots of fun to blow bubbles but it's wiser to prick them yourself before someone else tries to."

Nobel laureate Joshua Lederberg stated that Avery and his laboratory provided "the historical platform of modern DNA research" and "betokened the molecular revolution in genetics and biomedical science generally.