Erwin Chargaff
Erwin Chargaff, born 1905 in Czernowiz, Austria, was a pioneer in biochemistry
contributing to the understanding of DNA. He, in 1928, earned his doctoral
degree in chemistry at the University of Vienna\'s Spath\'s Institute in 1928.

Erwin began his career in biochemistry at Yale University, working under Rudolph

J. Anderson from 1928 to 1930. His early work included stories of the complex
lipids, the fats or fatty acids that occur in microorganisms. Helping discover
the unusual fatty acids and waxes in acid-fast mycobacteria led him to study the
metabolism and biological role of lipids in the body. Chargaff was also a
pioneer in the use of radioactive isotopes of phosphorus as a tool to study in
the synthesis and breakdown of phosphorus-containing lipid molecules in living
cells. He published a paper on the synthesis of a radioactive organic compound
called alpha-glycerophosphoric acid. He began to study nucleic acids in 1944,
while at Colombia. Until this time scientists believed that amino acids carried
genetic information. DNA was also believed to contain the tetranucleotides made
up of cytosine, thymine, adenine and guanine, that served as an attachment site
for the amino acids that made up genes. It was already known that a cell\'s
nucleus is comprised in part by DNA, Chargaff was able to determine how much of
which bases were present by measuring the amount of light each quantity of base
absorbed. He showed that adenine and thymine occur in DNA in equal proportions
in all organisms and that cytosine and guanine are also found in equal
quantities. Chargaff\'s major conclusion is that DNA carries genetic information,
and the number of different combinations in which the four nucleic acids appear
in DNA provides enough complexity to form the basis of heredity. Finally, he
concluded that the identity of combinations differs from species to species and
that DNA strands differ from species. Overall, his findings were important
contributions in biochemistry, including the addition of a key piece in the
puzzle of the structure of DNA. This all led to major developments in the field
of medical genetics, and, ultimately helped pave the way for gene therapy and
the birth of the biotechnology industry.