DNA

DNA

1. Background

   • Genetics study began 19th C. - Mendel showed how characteristics can be passed through generations
     • 20c - scientists took photos of cells through electron microscopes and X-Rays (crystallography)
   • Each cell in the body contains DNA; set of codes to control genes that decide eye colour etc.
     • If scientists could work out how genetic codes fitted together in DNA strands they could identify which genes called inherited conditions
       • Sickle cell anemia
       • Cystic fibrosis

2. Stages in discovery

   • Crick and Watson team up to build DNA model
     • Made use of other specialisms and were interested to hear of Wilkins and Franklins work
       • Franklin looked at DNA model and pointed out something that her photos showed was a mistake
         • Franklin gave Wilkins all her data. Wilkins showed Watson her clearest photo
           • Crick and Watson used Franklins photo to help complete model
             • Franklin wrote and published findings at the same time as Wilkins Watson and Crick

3. Impact

   • 1953 - Crick and Watson discover structure of DNA
     • 1990 - Human Genome Project (Watson led) wanted to map the location of every gene (30,000-35,000) in the 23 chromosomes in every cell
       • 2000 - Project involved hundreds of scientists working in 18 teams. First draft produced
         • Scientists have identified certain genes that pass on specific hereditary conditions
   • The Result
     • There are new techniques for skin grafts, better production of insulin and better vaccines
     • Better understanding of conditions (Downs syndrome, leukaemia) and whether people are more likely to develop some cancers
     • Further research to develop techniques to alter faulty genes and prevent genetic illnesses
     • *New Discovery*
       • Stem cells (bone marrow of long bones and pelvis) can transform into various cells used around the body - offers a chance to replace faulty genes with healthy ones