Scientists who discovered DNA, and how they did it

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Scientists who Discover DNA

Introduction

With the continuous search for better understanding of how really human body works and the reason of having different physical and behavioural attribution forced a lot of scientists around the globe to conduct researches regarding the true source of our identity and this is how these scientist lead to the discovery of DNA

Body

Actually , there is no single person that made the discovery of DNA There are a lot of scientists all over the world that work

hand in hand to have a better understanding of DNA . However it was John Friedrich Miescher who first successfully isolated DNA from the pus of discarded surgical bandages and called it nuclein ' in 1896 , he also has the idea that DNA is a genetic material (Dahm 2004 : 276 . This discovery of Miescher serves as the foundation of other researches about DNA on the following decades . In the 1920 's , another breakthrough on the field of DNA research happened when Phoebus Levene discovered that DNA is as string of sugar and phosphate nucleotide unit that is linked together and this serves to be the base of DNA . Levene also suggested that DNA is only a short chain having a repeated and fixed structure pattern but this idea was debunked by the X-ray diffraction produced by William Astbury in 1937 which showed that DNA has a regular structure and not fixed as to what Levene suggested before . Erwin Chargaff found out in 1949 that DNA has fixed proportions of adenine , thymine , guanine and cytosine which are also presently known as the base ratios that made vital link towards the discovery of DNA structure although Chargaff did not have any clue of how important his discovery is

In 1953 , another X-ray diffraction image of DNA was produced by Rosalind Franklin who was an expert on X-ray crystallography (Kane 2007 1 . With the help of Maurice Wilkins , Franklin was able to determine that the phosphate backbone of DNA can be found outside while bases can be found on the inside of DNA (BA-Education .demon .co .uk 2007 : 1 Moreover , she was also the one who established that the structure of DNA was a double helix as well as the strands are antiparallel to one another with a specific base pairing . Furthermore , Franklin was also able to found out that there are tow forms of hydration that can be achieved by bundling super thin strands of DNA and zapping them with a super X-ray beam namely A form which is dry , and B form which is wet see illustration below . The fuzzy cross on Franklin 's picture of B form of DNA indicated that DNA is indeed has a double helix form B Form of Double Helix in 1952 taken by Rosalind Franklin

On the other hand , James Watson and Francis Crick , after having a copy of all of Franklin 's data about the structure of DNA started to make research that the bases of DNA are paired and that DNA does not have a double helix form rather a multiple helix . Through the Chargaff 's rules Watson and Crick were able to discover the last piece of puzzle about the base pairing of DNA

On March 18 , 1953 , Watson and Crick published their work and earned the full credit from discovering the structure of DNA leaving Franklin with no recognition even if all of the data and starting idea came from the latter . On April 25 , 1953 , Watson and Crick published their entitled A Structure for Deoxyribose Nucleic Acid ' in Nature . By 1962 , Watson and Crick received their Nobel Prize in Physiology or Medicine and proposed that DNA molecule has a double helix structure like a twisted ladder (Essortment .com 2007 : 1 . Moreover , both of them stressed that the rails of the ladder is made up of alternating units of phosphate and sugar Deoxyribose while the rungs is made up of a pair of nitrogen containing nucleotides (Nobelprize .org 2007 : 1

Conclusion

The works of Watson and Crick serves as the foundation of modern researches about DNA even most of the efforts one the discovery of double helix structure of DNA came from Rosalind Franklin

Works Cited

BA-Education .demon .co .uk (2007 ) The People Responsible for the Discovery of DNA [online] . Available : HYPERLINK "http /www .ba-education .demon .co .uk /for /science /dnamain .html http /www .ba-education .demon .co .uk /for /science /dnamain .html [Accessed 25 February 2008]

Dahm , Ralf (2004 . Friedrich Miescher and the Discovery of DNA [online] Available : HYPERLINK "http /www .targeting-the-kinome .org /images /Friedrich_Miescher .pdf http /www .targeting-the-kinome .org /images /Friedrich_Miescher .pdf [Accessed 25 February 2008]

Essortment .com (2007 . Francis Crick and James Watson : DNA [online] Available : HYPERLINK "http /www .essortment .com /dnascientists_rchz .htm http /www .essortment .com /dnascientists_rchz .htm [Accessed 25 February 2008]

Kane , Heather (2007 . Who Discovered DNA ? [online] . Available HYPERLINK "http /elvis .engr .wisc .edu /UER /uer96 /author9 /index .html http /elvis .engr .wisc .edu /UER /uer96 /author9 /index .html [Accessed 25 February 2008]

Nobelprize .org (2007 . The Discovery of the Molecular Structure of DNA - The Double Helix [online] . Available : HYPERLINK "http /nobelprize .org /educational_games /medicine /dna_double_helix /readm ore .html http /nobelprize .org /educational_games /medicine /dna_double_helix /readmo re .html [Accessed 25 February 2008]

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