Editing Erwin Chargaff (section)

==Columbia University==
Chargaff immigrated to [[Manhattan]], [[New York City]] in 1935,<ref name=ssc>{{Cite journal|url=https://www.jstor.org/stable/1558287|jstor=1558287|title=Erwin Chargaff, 11 August 1905 · 20 June 2002|last1=Cohen|first1=Seymour S.|journal=Proceedings of the American Philosophical Society|year=2004|volume=148|issue=2|pages=222–228}}</ref> taking a position as a research associate in the department of biochemistry at [[Columbia University]], where he spent most of his professional career. Chargaff became an [[assistant professor]] in 1938 and a professor in 1952. After serving as department chair from 1970 to 1974, Chargaff retired as professor [[emeritus]]. After his retirement as professor emeritus, Chargaff moved his lab to [[Roosevelt Hospital]], where he continued to work until his retirement in 1992.{{citation needed|date=December 2011}}

He became an American citizen in 1940.

During his time at Columbia, Chargaff published numerous scientific papers, dealing primarily with the study of [[nucleic acids]] such as [[DNA]] using [[chromatographic]] techniques. He became interested in [[DNA]] in 1944 after [[Oswald Avery]] [[Avery-MacLeod-McCarty experiment|identified]] the molecule as the basis of [[heredity]].<ref name=avery44>{{cite journal|last1=Avery|first1=Oswald T.|last2=MacLeod|first2=Colin M.|last3=McCarty|first3=Maclyn|title=Studies on the Chemical Nature of the Substance Inducing Transformation of Pneumococcal Types – Induction of Transformation by a Desoxyribonucleic Acid Fraction Isolated from Pneumococcus Type III|journal=Journal of Experimental Medicine|date=February 1, 1944|volume=79|issue=2|pages=137–158|pmid=19871359|pmc=2135445|doi=10.1084/jem.79.2.137}}</ref><ref name=weintraub06/><ref name="mccarty03">{{cite journal |doi=10.1038/nature01398|title=Discovering genes are made of DNA |year=2003 |last1=McCarty |first1=Maclyn |journal=Nature |volume=421 |issue=6921 |page=406 |pmid=12540908 |bibcode=2003Natur.421..406M|s2cid=4335285|doi-access=free }}</ref> [[Seymour S. Cohen|Cohen]] says that "Almost alone among the scientists of this time, Chargaff accepted the unusual Avery paper and concluded that genetic differences among DNAs must be reflected in chemical differences among these substances. He was actually the first biochemist to reorganize his laboratory to test this hypothesis, which he went on to prove by 1949."<ref name=ssc/> Chargaff said of the Avery discovery: "I saw before me (in 1944), in dark contours, the beginning of a grammar of biology",<ref name=weintraub06/> and in 1950 he published a paper with the conclusion that the amounts of [[adenine]] and [[thymine]] in DNA were roughly the same, as were the amounts of [[cytosine]] and [[guanine]].<ref name=NucleotidePaper>{{cite journal|last1=Chargaff|first1=Erwin|first2=Stephen |last2=Zamenhof |first3=Charlotte |last3=Green |title=Composition of human desoxypentose nucleic acid|journal=Nature|date=May 1950|volume=165|issue=4202|pages=756–7|pmid=15416834|bibcode = 1950Natur.165..756C |doi = 10.1038/165756b0 |s2cid=33722052}}<!--|access-date=8 September 2011--></ref> This later became known as the first of [[Chargaff's rules]]. Instrumental in his DNA discoveries were the innovation of [[paper chromatography]],<ref name="consden44">{{cite journal |doi=10.1042/bj0380224|title=Qualitative analysis of proteins: A partition chromatographic method using paper|year=1944|last1=Consden|first1=R.|last2=Gordon|first2=A. H.|last3=Martin|first3=A. J. P.|journal=Biochemical Journal|volume=38|issue=3|pages=224–232|pmid=16747784|pmc=1258072}}</ref> and the commercially-available [[ultraviolet spectrophotometer]] tool.<ref name=weintraub06/>

Chargaff lectured about his results at [[Cambridge University]] in 1952, with [[James Watson|Watson]] and [[Francis Crick|Crick]] in attendance.<ref name=betz10>{{cite book|first=Frederick|last=Betz|title=Managing Science: Methodology and Organization of Research|url=https://books.google.com/books?id=1ARRexcXgAgC&pg=PA82|date=30 November 2010|publisher=Springer Science & Business Media|isbn=978-1-4419-7488-4}}</ref>