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.