Trace the history of the discovery of DNA...?

Question

Please....I need a brief history of the discovery of DNA

Answer 1

watson and crick discovered its structure through crystallography of Rosalind Franklin's. HErshey and Chase discovered it was the hereditary molecule. Mesalton and Stahl discovered its semiconservative mode of replication

Answer 2

DNA was known well-before Watson and Crick's time, it was acutally several other scientists who definitively proved that nucleic acids and not any type of protein were the heritable element, at least in bacteriophages. Work done by Oswald Avery and after by the famous A.D. Hershey and Marth Chase and a bit after conclusively excluded protein and RNA as the genetic material in this system, and thus by elimination DNA was thought to be the element of heredity. Watson and Crick essentially stole the X-ray crystollography data, taking it without permission from the person who did the experiments Rosalind Franklin, and came up with the double-helical structure we know today that has single-stranded complementary DNA running anti-parallel to eachother to form a stable molecule. Thus DNA has polarity, in that at one end there is a 5' phosphate, while at the 3' there is a hydroxyl group. They will only be complementary if they run anti-parallel to eachother. Erwin Chargaff actually came up with a major insight that Watson and Crick found essential, pyrimidines and purines were in equal quantities in DNA. In other words, the four bases of DNA came up in two pairs that were equal to eachother in concentration; A=T and C=G. We know this as Chargaffs rules, and is the foundation for the complementary Watson-Crick base pairing that was key to solving the structure of DNA. Also denaturation studies suggested that hydrogen bonds play a major role in DNA stability as a double-stranded molecule, and was in line with Watson-Crick base pairing since C-G has 3H bonds and those DNA with higher %GC had a higher melting temperature. Their finding has immediate implications for a simple way to replicate the DNA, since each strand has all the genetic information encoded within it and can act as a template for the newly synthesized strand.

Answer 3

DNA Deoxyribonucleic Acid was discovered over 50 years ago by James WAtson( american) and 3 british scientist ( Francis Crick, Maurice Wilkens and Rosalind Franklin) Watson and Crick announced their dicovery in a one page report i nthe Journal Nature in 1953 Wilkins did a more detailed paper on the chemistry of DNA