History of Dna

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Sergo Oganesyan

Mrs. Kelly

Science 10

History of DNA

The history of DNA starts in 1866 with Gregor Mendel, who was a monk from Moravia.

He is known for discovering the fundamentals of modern science of genetics. He discovered the

laws of inheritance. He discovered that genes usually come in pairs and are inherited as separate

units. Taking one from each parent. Mendel had 3 laws. The first law being the law of

segregation, which determines which traits the offspring adopts. The second law was the law

independent assortment. Which states that genes for different types of traits are independent and

are separated from each other. The last law is the law of dominance, an organism with more than

one pair of allele in the same locus will express the most dominant one. ("Mendel's Genetic

Laws")Following Mendels footsteps, Freidrich Miescher isolated the first crude preparation of

DNA while working with white blood cells. Miescher was researching the composition of

lymphoid cells at a laboratory. He used to gather bandages from clinics and wash off the pus

from lymph nodes. One day he came across a new molecule and isolated it, it was called a

nuclein. Which came from the cell nucleus. Friedrich published his research in 1971. Two

decades past and a man named Carl Enrich Correns showed interest in trait inheritance. Correns

and DeVries were the ones to redefine Mendels laws. Correns became the director of the Kaiser

Wilheim Institut Fr Biologie in Berlin. However, a lot of his work and research went

unpublished because of the Berlin Bombing. Alongside Correns, Hugo de Vries was working on

his own theories. He is known as the main proponent in the theory of mutation. Mutations are


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caused by errors in the transcription process of DNA into proteins but only occur very, very

rarely. ("DNA") He believed that species evolved from other species because of sudden large

changes of character trait. ("DNA Timeline: DNA Science from Mendel to Today")

A long while after, came Thomas Hunt Morgan. His main work revolved around the

years 1911-1928 where he was studying fruit flies along with his students. During that time he

established the theory of chromosomal inheritance, for that he received his Nobel Prize for

medicine in the year 1933. A student that was working for Thomas named Hermann Muller was

also highly involved in the history of genetic inheritance. He is most known for his work on his

nobel prize-winning research on how radiation is a cause of genetic mutations. A woman named

Barbara McClintock was working on supporting this evidence by testing the theory on corn. She

came to the conclusion that using radiation led to translocations, deletions, conversions, and ring

chromosomes. She is most known for the discovery of translocations. A friend of Barbaras

named George Beadle also came up with the hypothesis of the one gene one enzyme For this

he gained a Nobel prize after testing 300 different culture samples. ("DNA Timeline: DNA

Science from Mendel to Today")

Before Evelyn Witkin, soviet scientists believed that environment could affect and

change hereditary features. She disproved the idea of a Soviet scientist named Trofim Lysenko.

The structure of DNA was always a mystery to be unsolved until Rosalind Franklin, James

Watson, Maurice Wilkins, and Francis Crick. Rosalind Franklin was able to get 2 photos of high

resolution photos of the crystallized dna. She hypothesized that the structure of the DNA was a

helix. James Watson, on the other hand thought it was a double helix. Crick and and Watson

were never associated with Rosalind. It was Maurice that made a tie in between them. Maurice


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was passing Rosalinds results to Watson and Crick. And after Rosalind got data from her

workings with X-rays Watson and Crick confirmed that the structure of DNA was three

dimensional. They also confirmed Watsons hypothesis of the DNA being the double helix.

Watson, Wilkins, and Crick all got Nobel prizes whilst unfortunately Rosalind died from cancer

before receiving her award. With the knowledge of the structure of the DNA future scientists

were able to define parts of it and identify this complex molecule even further. ("DNA Timeline:

DNA Science from Mendel to Today") (Nuwer, "Counting All the DNA on Earth")

Citations:

"DNA."Basic Biology. Basic Biology, n.d. Web. 17 Sept. 2015.

.

"DNA Timeline: DNA Science from Mendel to Today."DNA Timeline: DNA Science from

Mendel to Today . DNAi.org, n.d. Web. 15 Sept. 2015. .

"Mendel's Genetic Laws."Mendel's Genetic Laws. N.p., n.d. Web. 17 Sept. 2015.

.

Nuwer, Rachel. "Counting All the DNA on Earth." The New York Times. The New York Times,

20 July 2015. Web. 17 Sept. 2015.

.
http://www.nytimes.com/2015/07/21/science/counting-all-the-dna-on-earth.html?_r=0


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History of Dna