Chargaff, Erwin

[person]

(also known as Edwin Chargaff) Austrian-Jewish biochemist born in Czernowitz, Ukraine (then part of Austria-Hungary) in 1905. Chargaff immigrated to the United States in 1935 and died in New York City in 2002. He is best known for discovering two rules about DNA chemistry that significantly advanced the field of molecular biology. Chargaff's First Rule is that the number of adenine base units in DNA is equal to that of thymine, and the number of cytosine base units is equal to that of guanine (A = T, C = G). This was an important clue for James Watson and Frances Crick as they worked on solving the molecular structure of DNA. The Second Rule is that the composition of DNA, in terms of the relative amount of A, T, G, and C bases, varies from species to species. This was significant evidence for Oswald Avery's hypothesis that DNA carries hereditary information.