Discuss about DNA related topic - Essay Example

DNA has come a long way since the time of the famous photo 51 of Rosalind Franklin until the three-dimensional model interpretation of Jim Watson and Francis Crick of the double helical structure of the DNA strand. Even the discovery of the DNA helix was of controversy itself as discussed in an interview of Lynn Osman Elkin conducted on March 26, 2003 posted at NOVA website regarding the confusion on who to take credit for the discovery, if double helix DNA should be more on Franklin’s account (Rosalind Franklins Legacy).

Deoxyribonucleic acid is the hereditary material in humans and almost all other organisms. Most DNA is located in the cell nucleus. The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people. The order, or sequence, of these bases determines the information available for building and maintaining an organism, similar to the way in which letters of the alphabet appear in a certain order to form words and sentences (DNA interactive).

Series of studies have proven the role of DNA as the gene carrier. Fred Griffith and his transforming principle experimented on mice by injecting strains of the S (smooth) and R (rough) form of the Pneumococcus bacteria. The experiment showed transformation of R from to its virulent form by somehow incorporating gene from the dead S form when mixed together. Furthermore Griffith’s experiment set out Oswald Avery and colleagues Colin Macleod and MacLyn McCarty to determine what the transforming agent was by the process of elimination ruling out DNA as the transforming material.

Further experiment of Hershey and Chase proved that DNA, and not protein, is the one injected by virus into their host thus establishing DNA as the hereditary