-
MENDEL: research on experiments in plant hybridization
VIDEO ON MENDEL EXPERIMENTSGregor Mendel, an Augustinian monk, between 1956 and 1963 started using a monastery garden for crossing pea plant varieties and descovered how traits are passed down from parents.
For example, when he crossed yellow peas with green peas, all the offspring peas were yellow. But when these offspring reproduced, the next generation was ¾ yellow and ¼ green. Mendel’s work, which was presented in 1865, showed that what we now call “genes” determine traits in predictable ways. -
MIESCHER: identification of "nuclein," DNA with associated proteins, from cell nuclei
At he University of Tübingen (in Switzerland) he researched white blood cells. He took them from bandages with infectious materials, full of them. In 1869, he isolated a new molecule from the cells’ nuclei and called it “nuclein.” Nuclein contained hydrogen, oxygen, and a unique ratio of phosphorus to nitrogen. Although Miescher studied nuclein throughout his career, he and other scientists believed proteins were the molecules by which traits passed from parents to children. -
The first enzime is discovered and isolated
-
Wilhelm von Waldeyer: the chromosome is discovered
-
-
ROSALIND FRANKLIN: Photograph 51, showing a distinctive pattern that indicates the helical shape of DNA
The discovery happened when she was researching at s King’s College in London where Maurice Wilkins, a physicist and molecular biologist, was using X-ray crystallography to study DNA. Franklin took two sets of high-resolution photos of crystallized DNA fibers and looked at the dimensions of DNA strands, with phosphates on the outside of what appeared to be a helical structure. -
WATSON AND CRICK: the double helix structure of DNA
To modeled the structure of DNA, they used paper cutouts of the bases (A, C, G, T) and metal scraps from a machine shop. Their model represented DNA as a double helix, with sugars and phosphates forming the outer strands of the helix and the bases pointing into the center. Hydrogen bonds connect the bases, pairing A–T and C–G; and the two strands of the helix are parallel but oriented in opposite directions. -
NIRENBERG: cracking of the genetic code for protein synthesis
In the early 1960s, Marshall Nirenberg and National Institutes of Health colleagues focused on how DNA directs protein synthesis and the role of RNA in these processes. In 1961, uaing a synthetic messenger RNA (mRNA) strand that contained only uracils (U), they discovered a protein that contained only phenylalanines. Identifying UUU as the RNA code for phenylalanine was their first breakthrough. Within a few years, Nirenberg’s team had cracked the 60 mRNA codons for all 20 amino acids. -
COHEN AND BOYER: first seccessful recombinant DNA experiments
-
An Enzime is siythetized in vitro for the first time
-
SANGER: rapid DNA sequencing technique
The “rapid DNA sequencing” technique, or "Sanger method", determines the order of bases in a strand of DNA. Special enzymes are used to synthesize short pieces of DNA, which end when a selected “terminating” base is added to the stretch of DNA being synthesized. Typically, each of these terminating bases is tagged with a radioactive marker, so it can be identified. Then the DNA fragments, of varying lengths, are separated by an electric field (electrophoresis) -
KARY MULLIS: polymerase chain reaction technology for amplifying DNA
The Polymerase Chain Reaction (PCR) is a relatively simple and inexpensive technology used to amplify or make billions of copies of a segment of DNA. One of the most important scientific advances in molecular biology, PCR amplification is used every day to diagnose diseases, identify bacteria and viruses, and match criminals to crime scenes. PCR revolutionized the study of DNA to such an extent that Dr. Mullis was awarded the Nobel Prize in Chemistry in 1993. -
Cystic Fibrosis gene mutation identified
Cystic fibrosis (CF), a life-threatening genetic disease that causes thick, sticky mucus to build up in the lungs, digestive tract, pancreas, and other organs, is one of the most common chronic lung diseases in children and young adults. -
Prooved existence of a gene against tumor
BRCA1 (BReast CAncer gene 1) is a “tumor suppressor gene,” which normally produces a protein that prevents cells from growing and dividing out of control. However, certain variations of BRCA1 can disrupt its normal function, leading to increased hereditary risk for cancer. The first evidence for existence of the BRCA1 gene was provided in 1990 by the King laboratory at University of California Berkeley. After a heated international race, the gene was finally isolated in 1994. -
THE HUMAN GENOME PROJECT BEGINS
Beginning in 1984, the U.S. Department of Energy (DOE), National Institutes of Health (NIH), and international groups held meetings about studying the human genome. In 1988, the National Research Council recommended starting a program to map the human genome. The project would develop technology for analyzing DNA; map and sequence human and other genomes – including fruit flies and mice; and other genomes – including fruit flies and mice; and study related ethical, legal, and social issues. -
The first gene therapy is approved federally and succedes
The patient was a 4-year girl suffering from an immune disorder -
Haemophilus influenzae the first bacterium genome sequenced
-
“Bermuda Principles” : free access to data of Human Genome project
At a 1996 summit in Bermuda, leaders of the Human Genome Project agreed that all human genomic sequence information generated by centers funded for large-scale human sequencing should be made freely available and in the public domain within 24 hours after generation. -
Human chromosome 22 decoded!
When the sequence of human Chromosome 22 was first reported in 1999, it was the longest, continuous stretch of DNA ever decoded and assembled. Chromosome 22 was chosen as the first of the 23 human chromosomes to decode because of its relatively small size and its association with several diseases. Seeing the organization of a human chromosome for the first time at the base-pair level paved the way for the rest of the Human Genome Project. -
Genome of Drosophila melanogaster registered
Organisms such as the fruit fly, Drosophila melanogaster, have been crucial for identifying the functions of human genes. In 2000, a consortium of scientists released a substantially complete fruit fly genome sequence, obtained using several different but complementary sequencing strategies. -
First draft of the human genome released
In 2001, the Human Genome Project international consortium published a first draft and initial analysis of the human genome sequence.
For instance, the number of human genes was estimated to be about 30,000 (later revised to about 20,000). Researchers also reported that the DNA sequences of any two human individuals are 99.9 percent identical. -
Mouse Genome Decodified
This milestone was all the more significant because of the widespread use of the laboratory mouse as an animal model for studying human disease. Among other informative discoveries, researchers reported that more than 90 percent of the mouse genome could be aligned with corresponding regions of the human genome, and each of the two genomes seemed to contain close to 30,000 protein-coding genes. -
Human Genome Project completion announced
VIDEO: IMPACT OF HUMAN GENOME PROJECTThe sequences produced by the Human Genome Project in 2003 covered about 99 percent of the human genome's gene-containing regions. The project was finished two-and-a-half years ahead of time, and was also significantly under budget.
The discovered genomes of organisms have been used in disease research, in the projecting new technologies for studying whole genomes
