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The Scientists behind the Discovery of DNA

Name of Scientist Work contributed to inheritance and DNA

Linus Pauling In the 1950s, Linus Pauling became known as t he founder of molecular

biology due to his discovery of th e spiral structure of proteins. Paulingsdiscoveries contributed to Watson and Cricks breakthrough of the DNAdouble helix.Pauling made it possible for geneticists to crack the DNA code of allorganisms and develop techniques to help prevent the inheritance ofgenetic disorders.

Rosalind Franklin Franklin was instrumental in discovering there were two forms of DNA.When wet, DNA fibres became long and thin, called the B form, and whendried it became short and fat, labelled the A form. In 1951 Franklinpresented this information in a lecture in Cambridge where James Watsonwas present. Importantly Franklin indicated that DNA was likely to be a

double helix with anti-parallel strands and that it had a phosphatebackbone on the outside. Within this context the double bases of DNA,the code for inheritance, was envisaged to be on the inside of the helix.

Maurice Wilkins Wilkins began studying nucleic acids and proteins via X-ray imaging. Hewas very successful in isolating single fibres of DNA and had alreadygathered some data about nucleic acid structure when Rosalind Franklin,an expert in X-ray crystallography, joined the unit.

James Watson In 1953, James Watson and Francis Crick, working on X-rays of DNAcrystals produced by Rosalind Franklin, deduced that the molecule musthave a double helix structure. This immediately suggested howinheritance might work.

Francis Crick (see above) Francis Crick also worked on the double helix model withWatson

Friedrich Meischer Meischer studied the nucleus; he first identified what he called "nuclein"inside the nuclei of human white blood cells. (The term "nuclein" was laterchanged to "nucleic acid" and eventually to "deoxyribonucleic acid," or"DNA.") Miescher's plan was to isolate and characterize the proteincomponents of leukocytes (white blood cells). Miescher used pus toextract and identify the various proteins within the white blood cells. Ehenhe came across a substance from the cell nuclei that had chemicalproperties unlike any protein, including a much higher phosphorouscontent and resistance to proteolysis (protein digestion), Miescher

realized that he had discovered a new substance.Gregor Mendel Gregor Mendel, through his work on pea plants, discovered the

fundamental laws of inheritance. He deduced that genes come in pairsand are inherited as distinct units, one from each parent. Mendel trackedthe segregation of parental genes and their appearance in the offspring asdominant or recessive traits.

Matthew Meselon andFrank Stahl

The Meselson Stahl experiment was an experiment which supported thehypothesis that DNA replication was semiconservative. Insemiconservative replication, when the double stranded DNA helix isreplicated each of the two new double-stranded DNA helixes consisted ofone strand from the original helix and one newly synthesized

http://en.wikipedia.org/wiki/DNA_replicationhttp://en.wikipedia.org/wiki/Semiconservative_replicationhttp://en.wikipedia.org/wiki/DNAhttp://en.wikipedia.org/wiki/DNAhttp://en.wikipedia.org/wiki/Semiconservative_replicationhttp://en.wikipedia.org/wiki/DNA_replication

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Charles Darwin andRussel Wallace

In the mid-1800s, Darwin and the British biologist Alfred Russel Wallaceindependently conceived of a natural, even observable, way for life tochange: a process Darwin called natural selection.

Barbara McClintock Barbara Mcclintock made an important contribution in many areas ofstudy in the field of genetics, by decoding the genetic transfer of

information between two chromosomes and the clarification of telomereand centromere phases of cell replication.