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What is DNA Sequencing?
What is DNA Sequencing?
What is DNA Sequencing?
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Sequencing the History of DNA Sequencing
1953
In early 1951, Watson and Crick began to understand that in order to understand reproduction and hereditary science, one needed to be highly knowledgeable about subjects such as biology, chemistry, physical chemistry and X-ray crystallography. They prepped hard for the next eighteen months of their lives and focused their attention strictly on these sciences. After borrowing a substantial amount of experiments from other scientists and failing to describe the complexity of DNA came a day when they met Jerry Donohue, a physical chemist from the U.S. After his advice to take card boards and to set it up as though they were actual molecules present in the DNA structure helped Watson and Crick to reach their discovery of the DNA structure.
1965
When scientists first wanted to tackle DNA sequencing, the process was extremely intimidating. The DNA strands were extremely long for synthesis, the chemical properties of DNA were not distinct as much as RNA or any other micro molecule which made it difficult to differentiate between the bases, and the fact that DNA had only four bases in comparison to proteins which have 20 amino acids to help in their differentiation made the process harder. Moreover, there wasn’t any knowledge of any deoxyribonuclease (DNase) that could possibly degrade DNA, thus protein sequencing had to depend on amino acids on its own. At the time of struggles, scientists turned their attention to RNA which was a much more simpler version of a DNA and could be further purified. Moreover, RNA had bases that were known so methods analogous to protein sequencing could be applied in this case as opposed to DNA where the base specificity was veiled. Therefore, in 1965. Holley and his colleagues went ahead and sequenced tRNA alanine from Escherichia Coli. Further base pairing techniques allowed scientists to deduce the sequence of RNA since it didn’t need any intricate methods like crystallography.
1970
The discovery of type II restriction enzymes opened up the next door in the path of researchers in the field of DNA sequencing. Hamilton Smith and coworkers found enzymes that caused the degradation of DNA at specific points. They also came to find out that these enzymes could be further identified through the screening of bacterial strains and specifically spliced DNA at certain points. Further in the process, these enzymes cleaved into the DNA strands and created several smaller strands which were then run through gel electrophoresis and allowed to be sequenced using the sequencing methods developed.
1977
Sanger Method of sequencing and the Maxam Gilbert Method of sequencing is developed.
1983
Kary Mullis, a DNA chemist figured out the process of PCR (polymerase chain reaction) while driving from San Francisco to Mendocino one day. He was a chemist at the Cetus Corporation outside of San Francisco where he worked seven years of his life. His research was based upon the synthesis of oligonucleotides which are short DNA sequences made of around 20 bases. The PCR process magnified the genetic material stored within the DNA.
1986
The arrival of the Ph.D, Mike Hunkapiller in the company, Applied Biosystems in the year of 1983 allowed the company to grow from a startup company to a $2 billion company that provided things such as reagents, other technologies and for the first time in 1986, an automated sequencer with a four color fluorescence. Applied Biosystems has been a company to provide the world with the development, production and marketing of mass spectrometry machines. Their technologies have aided several health care workers to discover novel things in the field of medicine and genomics.
1990
In 1986, the United States Department of Energy passed its decision to start the Human Genome Project in order to protect the human genome from any further radiation in the future. Alongside this step, the Congress supported the Department of Energy (DOE) and National Institutes for Health (NIH) to form a coalition and sign a Memorandum of Understanding to work together on the project for the betterment of the society as a whole. Several different discoveries on DNA itself through the work of Watson and Crick and DNA sequencing allowed us to take this major step in history. In 1990, the plan was to set specific goals and to see where the progress at halted in the course of five years. Afterwards, another 15 years would be taken to conduct further research, This research plan was known as "Understanding Our Genetic Inheritance: The Human Genome Project, The First Five Years, FY 1991-1995”.
1995
After the commencement of the process of genome sequencing, it became important to sequence the genes of more than just one species of organism which were human beings. After leaving NIH in 1992, J. Craig Venter founded the The Institute of Genome Research where he applied a method of shotgun sequencing to sequence the genes of the bacteria, Haemophilus influenzae Rd. He joined his efforts with Hamilton Smith of the John Hopkins University Medical School to sequence the genome of this bacteria who had a genome ten times the length of any normal virus. In the simplest of terms, this process was going to use a sector of the entire DNA present in the bacterium to discover all of the sequences by the end using computational methods. First, pieces of DNA were cleaved into several different lengths. Some had lengths between 1,000-2,000 base pairs while others were from 16,000-20,000 base pairs. A TIGR assembler was utilized in order to analyze these strands. The more informative sequences were identified first while other strands with repeating sequences were processed later on. This process turned out to be a success with around 1,830,137 base pairs, all of which combined to form 1,729 genes. This process took an year to complete.
1996
Citations 1.1 - 1.13
Citations 1.1 - 1.13
During a DNA polymerization process, Pal Nyren’s group at the Royal Institute for Technology noticed that pyrophosphate (inorganic biphosphate) was released. They began to figure out that natural nucleotides can be used to have “efficient incorporation” during a SBS process. The first step was to use a dATPaS instead of dATP. This made non-specific signals possible since dATP was meant to be a substrate for luciferase. However despite the lack of these enzyme, dATPaS was efficient at performing the needed work. Next, an apyrase was also added to the system in order to create a four-enzyme system where nucleotides could be continuously added with the need for any washing stop in between. The enzymatic reaction results in the generation of light which is then captured by a CCD camera and recorded as peaks on a pyrogram.
Citations 1.1 - 1.13
2000
The next generation sequencing method is introduced by Lynx Therapeutics through a method called MPSS (massively parallel signature sequencing). In this method, thousands of mRNA strands are sequences and then compared to the genome of A. thaliana, a plant species native to Eurasia. It allowed for the discovery of 1,168 genes that were previously unknown. One of the most significant things about this process is the fact that plant species, likewise all of the other species of organisms out there may have a much more complex composition then ever known to mankind. Everything on the surface is not exactly as it seems to be.
2003
In 2003, the entire sequencing of the human genome is complete and we come to discover 30,000 genes in our system. By the end of the process, the energy and health agencies not only had their goals fulfilled but also had high-quality version of the human sequence including a physical and genetic map of the human genome. Alongside the human genome, several other organisms such as mice also had their genomes sequenced.
2004
454 Life sciences completes and markets pyrosequencing. This technology was borne out of the second generation of sequencers.
2006
In 2006, Illumina creates the next line of DNA sequencing, called the Next-generation sequencing. This type of sequencing allows one to sequence whole genomes in a faster amount of time, be able to zoom into specific regions of the genetic molecule, be able to quantify mRNA, analyze the interaction between DNA and protein molecules and to study the diversity present in the very cells of human beings and other organisms on Earth.
2010
By the time it is 2010, the company, Life Technologies market numerous DNA sequencing technologies into one. Some of the examples include semiconductor sequencing, capillary electrophoresis sequencing & Fragment Analysis, Next-Generation Sequencing, Epigenetic Sequencing and RNA & Transcriptome Sequencing.
Citations: 10.1 - 10.3
Exploring the Depths of Life
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Sequencing
