|Born||Aug. 11, 1905
|Died||June 20, 2002 (at age 96)
New York City, USA
Erwin Chargaff was an Austrian biochemist. After the Nazis took power, he moved to the United States and joined the medical school at Columbia University as a biochemistry professor. He became a U.S. citizen in 1940.
Chargaff’s assiduousness in his experimentation produced rules that laid the groundwork for the eventual discovery of DNA’s structure: the double helix. To the surprise of many of his contemporaries, and to his own unhappiness, Chargaff was never named a Nobel laureate.
Early Life and Work
Chargaff was born on August 11, 1905, in Czernowitz in what is now Ukraine but was then part of the Austro-Hungarian Empire. After a conventional early education, he went to Vienna in 1924 to study chemistry, and remained there for four years. During this time, he earned his doctorate. In 1928, he traveled to the U.S., having been named a research fellow at Yale. After two years, he left as he did not like his surroundings, and returned to Europe.
Chargaff stayed in Europe for the first half of the 1930s, working at the University of Berlin until 1933. He worked in the department of bacteriology and public health there as a senior chemistry assistant. However, when the Nazis came to power in 1933, his Jewish background meant that he was required to resign his post. He moved to Paris and spent a year in the city at the Pasteur Institute, working as a research assistant.
Despite his earlier bad experiences at Yale, Chargaff decided to emigrate to the U.S., arriving in New York in 1935. He found a position at Columbia University’s biochemistry department as a research associate. It was here that he would spend most of his working life. He was named an associate professor in 1938, though WWII delayed his advancement to full professorial status until 1952. In 1970, he retired as professor emeritus, then moving to Roosevelt Hospital until 1992, when he retired completely from research.
While he was at Columbia, Chargaff’s published papers concentrated on the chemistry of nucleic acids, including the still poorly understood DNA, beginning in 1944. He made considerable use of chromatography in this work. By 1952, Chargaff had built on the earlier discoveries of Oswald Avery to demonstrate that DNA possessed roughly equal proportions of adenine, thymine, cytosine, and guanine. This was later to be formalized as Chargaff’s Third Rule.
However, the two most important rules that Chargaff formulated are generally considered to have had a greater influence in later DNA research. The first of these came when he showed that DNA, in its naturally occurring state, the count of cytosine and guanine units was close to identical, and that the same equivalency existed between thymine and adenine.
Although Chargaff did not explicitly state that this supported DNA’s base pair makeup – a necessary factor in its double-helix shape – the rule strongly hinted that this would be the case, and so Chargaff was acknowledged as the one who disproved the more popular tetranucleotide hypothesis.
Chargaff further proved that the small deviations from precise equivalency found in DNA – in humans, for example, guanine and cytosine are found in about 20% abundance; the others in about 30% – were genuine, rather than being the result of errors in experimentation as had previously been thought. He also showed that the cytosine/guanine pair was usually the less common. Chargaff made considerable use of new techniques like paper chromatography and UV spectrophotometry to support his conclusions.
Chargaff’s Second Rule
While in Cambridge in 1952, Chargaff met with Francis Crick and James D. Watson, who would go on to be key players in the discovery of the double helix. They had a fractious personal relationship, but Chargaff nevertheless passed on his experimental findings, which would prove crucial in the other men’s later work.
He also detailed what had come to be known as Chargaff’s Second Rule: that the relative abundance of the four constituents of DNA varied according to the species of the animal under discussion. This molecular diversity finally made DNA the favorite candidate for its genetic role, rather than proteins as had previously been suggested.
From the 1950s onward, Chargaff became unhappy with the state of his specialized field, arguing that molecular biology had moved beyond what he saw as its proper role of investigation, and moving into what he called “things that can never be justified.” He strongly believed that the world could not be treated simply as a machine that could eventually be completely understood. Instead, Chargaff stated his belief that the world was a complex, interdependent and interconnected system, and that genetic engineering would be almost certain to bring with it unforeseen and possibly even disastrous consequences.
Chargaff’s Later Years
Chargaff was so worried by the potential for genetic engineering to adversely affect the functioning of the global ecosystem that he said he thought it exceeded even the nuclear threat in its gravity. He continued to speak out on this subject for some years, although his most prominent public utterance came in 1962.
When Crick, Watson, and Maurice Wilkins were awarded the Nobel Prize in 1962, Chargaff made a public protest and withdrew from his own laboratory work. He was, however, awarded the National Medal of Science in 1974. Chargaff died at the age of 96 on June 11, 2002.