Why is erwin chargaff famous

Two major facts were already known about DNA. The first was that it is contained in the nucleus of every living cell. The second was that, in addition to sugar 2-deoxyribose and phosphate, DNA is composed of two bases: pyrimidines, of which there are two types cytosine and thymine , and purines, of which there are also two types adenine and guanine.

In addition, two important experimental methods involving paper chromatography and ultraviolet light absorption had recently been developed. To test the idea that DNA might be a primary constituent of the gene, Chargaff performed a series of experiments. He fractionated out nuclei from cells. He then isolated the DNA from the nuclei and broke it down into its constituent nucleic acids.

Then, using paper chromatography, he separated the purines and the pyrimidines. This was done on the basis of the solubility of the substances being analyzed a piece of chromatography paper is dipped into the solution and the different components of the solution travel different distances up the paper: the most soluble component travels the farthest up, to the driest section of the paper, and so on. He next exposed the separate components of the solution to ultraviolet light.

Because each base absorbs light of a different, "characteristic" wavelength, he was able to determine how much of which bases are present in DNA. What Chargaff discovered was that adenine and thymine exist in equal proportions in all organisms, as do cytosine and guanine, but that the proportions between the two pairs differ depending on the organism. Chargaff drew the conclusion that it is in fact the DNA in the nucleus of the cell that carries genetic information rather than the protein.

His argument was that, while there were only four different nucleic acids, as opposed to 20 proteins, the number of different proportions in which they could exist and the many different orders in which they could be present on the DNA strand provided a basis of complexity sufficient for the formation of genes. He also realized that there must be as many different types of DNA molecules as there are species.

Chargaff's conclusions revolutionized the biological sciences. E rwin Chargaff was born in Chernivtsi, a provincial capital of the Austro-Hungarian Empire, in After graduation he completed a one-year fellowship at Yale University before returning to Europe, where he became an assistant at the University of Berlin in Chargaff was, however, Jewish, and new Nazi policies, put in place when Hitler came to power in , excluded Jews from academic positions.

As a result, he left Germany for France. After a brief stint at the Pasteur Institute, he went back to the United States, and in started his lifelong career at Columbia University. He became a U. While Chargaff was growing up, his family had been fairly well off, but the Great Inflation after World War I brought financial ruin, and his father, the owner of a small bank, lost his business. His mother survived her husband, who passed away in , but she ended a victim of the Holocaust.

He cherished the outsider's role, modelling his sardonic view of the world on the writings of Karl Kraus, the Viennese satirist, whom he described as his only teacher. When people told Chargaff he was a misfit, he agreed.

A professor from onwards, he retired to emeritus status in , though his time at Columbia did not end happily. He was locked out of his office and exiled to a distant building. When a new chairman of biochemistry invited him back, Chargaff declined, choosing to add that, in the event of his death, "my simple request is: I do not want to be remembered by the university". The following correction was printed in the Guardian's Corrections and Clarifications column, Friday July 5 In our obituary of the biochemist Erwin Chargaff, we said he accused scientists of "practising biology without a licence".

What he spoke against, according to his autobiography Heraclitean Fire, published in by Rockefeller University Press, was "the practice of biochemistry without a licence". This article was also amended on 30 October The original had said that Oswald Avery was a Nobel prize winner. This has been corrected. Erwin Chargaff. Disillusioned biochemist who pioneered our understanding of DNA. His only son, Thomas, survives him.