dna- the source of heredity

          Deoxyribonucleic acid (DNA) was discovered in 1869, 10 years after the publication of Darvin`s « The Origin of Species». The Swiss biochemist Friedriech Meischer isolated a sample of DNA from white blood cells in pus sticking to discarded bandages. At this time there was no suspicion of the immense significance of the molecule as the «vehicle» of heredity and evolution. Not untill 1944 did Osvald Avery demonstrate that DNA was the matetial that transferred genetic information from one cell to another.
            The development of science often builds on previous results. Elucidating the structure of DNA would have been impossible without the discovery of X-rays could be used to find the arrangment of atoms in crystals. The method was successfully applied to determine the structure of proteins. Then, in 1952, Rosalind Franklin, working with  Maurice Wilkins, shone X-rays onto crystalline forms of DNA and produced diffraction patterns.
            Since the publication of the structure of DNA in 1953, there has been a dramatic increase in the amount of information and technology available for research. This has generated some of the most amasing opportunities for understanding bur also raised some of the gravest ethical qwuestions. Our understanding and ability to manipulate genetic material has led, for instance, to possibilities for gene therapy in a range of health disorders, genetic modification of crops, and the production of medically useful anti bodies and proteins in cloned animals. One major breakthrough, in 2001, was the completion of the «map» of the entire human genome (all the DNA in a call). As scientists explore how this information can be used, the  significance of this immense project can only increase.