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DNA Timeline
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Gregor Mendel discovers the basic principles of genetics
Mendel conducted experiments on pea plants, attempting to crossbreed in specific combinations. He identified seven characteristics.He found that when a yellow pea plant and a green pea plant were bred together their offspring was always yellow. However, in the next generation of plants, the green peas returned in a ratio of 3:1.Mendel coined the terms 'recessive' and 'dominant' in relation to their traits. -
Frederick Griffith
Came up with the basis that DNA was the molecule of inheritance. His experiment involve mice and two tyoes of pneumonia, one was virulent the other wasnt . He injected some mice with the virulent and with the non-virulent. The mice with the virulent died the other with the non-virulent didnt. Then he heated both the virulent and non-virulent and injected the mice with them. The results were reversed, the virulent didnt kill the mice but the non-virulent did when heated. -
Oswald Avery identifies DNA as the 'transforming principle'
After many years of research Avery discovered that if a live but harmless form of pneumococcus was mixed with an inert but lethal form, the harmless bacteria would soon become deadly. So he and some colleagues began to purify twenty gallons of bacteria. He soon noted that the substance did not seem to be a protein or carbohydrate but rather a nucleic acid, and with further analysis, it was revealed to be DNA. -
Erwin Chargaff discovers that DNA composition is species specific
After doing research and experiments Chargaff concluded that in any double-stranded DNA, the number of guanine units is equal to the number of cytosine units and the number of adenine units is equal to the number of thymine units, and second that the composition of DNA varies between species. This was knwn as 'Chargaff's Rules'. -
Rosalind Franklin photographs crystallized DNA fibres
Conducted a large portion of research that led to the discovery of DNA structure. Was also able to produce two sets of high-resolution photographs of DNA fibres. Using the photographs, she calculated the dimensions of the strands and also deduced that the phosphates were on the outside of what was probably a helical structure. -
Hershey and Chase
Conducted a series of experiments to confirm the DNA is genetic material. They used bacteriophage, for their experiments. The phage infects a bacterium by attaching to it and injecting its genetic material into it. -
James Watson and Francis Crick discover the double helix structure of DNA
They determined that the structure of DNA was a double-helix polymer, or a spiral of two DNA strands, each containing a long chain of monomer nucleotides, wound around each other. According to their findings, DNA replicated itself by separating into individual strands, each of which became the template for a new double helix. -
Test Tube Babies
A test-tube baby is the product of a successful human reproduction that results from methods beyond sexual intercourse but instead utilizes medical intervention that manipulates both the egg and sperm cells for successful fertilization. -
DNA evidence
Dr. Alec Jeffreys, discovered that certain areas of the DNA strand contain patterns that repeat many times. The number of these repetitions varies between individuals and Dr. Jeffrey developed a test that to measure the variation in length of these repretitions. Jeffrey found out that he could identify individuals by comparing smaples of their DNA. -
Dolly the shep
Dolly was the first mammal to be cloned from an adult cell. Dolly's subsequent survival proved that adult cells can reprogram themselves into a new being -
Human Genome
The human genome is the complete set of nucleic acid sequence for humans, encoded as DNA within the 23 chromosome pairs cell nuclei and in small DNA molecule found within individual mitochondria. -
CRISPR
New technology that can quickly destroy or edit a gene. CRISPR stands for clustered regularly interspaced short palindromic repeat.
