- slide 1 of 5
Early Research in Genetics
A timeline of DNA history:
1866 - Gregory Mendel observes that certain 'factors' were passed on from parent to offspring during his work on the hereditary of pea plants. These 'factors' would later become known as genes.
1869 - Friedrich Miescher identifies an acidic substance from the nuclei of cells derived from soiled bandages. The substance was initially called 'nuclein', but would eventually be known as deoxyribonucleic acid, or DNA.
1928 - Frederick Griffith observes that a 'transforming factor' was responsible for changing the properties of bacteria. The experiment consisted of injecting a dead strain of disease-causing bacteria into a mice, along with a live strain that doesn't cause disease. The result was that the live strain became virulent by obtaining some component from the dead strain.
1929 - Phoebus Levene concludes that DNA is made up of nucleotides which consist of a sugar, phosphate group, and a base.
1944 - Several scientists, including Oswald Avery, determine that the 'transforming factor' observed by Frederick Griffith was DNA and not a protein.
- slide 2 of 5
The Structure of DNA
1950 - Erwin Chargaff determines that the amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine. These four bases constitute DNA.
1952 - Alfred Hershey and Martha Chase establish that DNA is responsible for heredity by showing that viral DNA initiates the replication of new viruses. Maurice Wilkins and Rosalind Franklin image DNA crystals using X-Rays.
1953 - James Watson and Francis Crick describe the structure of DNA as a double helix consisting of two strands of DNA that are held together by base pairs.
- slide 3 of 5
1966 - Several scientists, including Marshall Nirenberg, discover 64 combinations of bases within the genetic code. Each combination consists of three bases.
1972 - Paul Berg uses restriction enzymes to cut DNA and splice together different DNA segments to create the first strand of recombinant DNA.
1980 - Genetically modified organisms can be patented, according to the US Supreme Court.
1982 - Humulin, a form of insulin produced by bacteria cultures, is the first genetically engineered drug.
1985 - Kary Mullis develops polymerase chain reaction, PCR, which is a technique that produces large amounts of a specific DNA sequence.
- slide 4 of 5
The Human Genome
1986 - Sequencing the human genome becomes an important goal for the scientific community.
1987 - Tommie Lee Andrew is the first person in the US to be convicted of a crime based on DNA evidence.
1989 - The Cystic Fibrosis gene is discovered by Francis Collins and Lap-Chee Tsui.
1990 - Gene therapy is successfully used on a patient for the first time.
1993 - The gene responsible for Huntington's disease is discovered.
1994 - A genetically modified tomato gets the approval of the FDA.
1995 - DNA testing in the O.J. Simpson trial is scrutinized.
2000 - An initial draft of the human genome is presented.
2003 - The entire human genome is sequenced.
Timeline of DNA history.
- slide 5 of 5