Genomics
...Boys are made of Snakes and snails and puppy dog tails
... girls of Sugar and spice and everything nice
What is life? What are we made of? One way to find out would be to make life, on the theory that if you can manufacture something from defined ingredients, you have a pretty good understanding of what it is. Building a cell from scratch no longer appears impossible. In the future we will be able to do just that
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| In nearly every cell of every living organism there exists a complete set of instructions for creating that organism and regulating its cellular structures and activities over its lifetime. That set of instructions is called a genome.
A genome is organized into distinct, microscopic units called chromosomes. Chromosomes are coiled threads of deoxyribonucleic acid--DNA--which is composed of two long chains of nucleotides bound together in pairs to form a double helix. Three and a half billion of these nucleotide pairs make up the human genome.
Specific sequences of nucleotide bases within a DNA strand--called genes--are the cells' instructions for producing proteins. Scientists estimate that 80,000 to 100,000 of these basic units of heredity exist within the human genome. Proteins perform a wide variety of physiological tasks. They facilitate processes such as digestion, breathing, immune responses, the production of heat and energy, and the movement of fluids in and out of cells.
While most members of a species have the same collection of genes, each individual's unique characteristics stem from slight variations--called polymorphisms--in the sequence of the nucleotides that comprise the genes of that individual. On average, the DNA of any two individuals will differ by about 0.1%.
Other types of variations--called mutations--also occur. Both polymorphic and mutagenic variations may be harmful to an individual by inhibiting the production, or altering the normal function, of a protein. Most diseases result from these types of genetic variations.
The goal of genomic inquiry is to identify the sequence of nucleotides, understand the function of every gene they comprise, and clarify the genetic variations that define individuality and create disease.
Diagnostics
Two major areas of diagnostics - risk assessment and personalized medicine - will benefit from genomics.
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Risk Assessment |
Predicting whether someone is at special risk for a particular disease has historically focused on measuring general indicators in the body, such as blood pressure and cholesterol levels. These measurements reflect general physiology but do not explain the specific genetic basis of disease in an individual patient. As a consequence, these diagnostic tests do not address the underlying cause of disease and can result in compromised medical care for patients and increased risk of litigation.
New genomic-based diagnostics will focus on determining an individual's risk of developing a particular disease by looking at specific genes and any disease-related changes in that patient. These new diagnostics will likely lead to far better preventive care by offering more accurate assessments of a patient's potential risk for developing a particular disease.
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Personalized Medicine |
Genomic information will be used to develop molecular diagnostic tests to identify the genetic make-up of individuals. These diagnostic tests will revolutionize medicine by enabling physicians to establish therapies designed for each patient--personalized medicine.
For example, many types of cancer that are distinct at the cellular level nevertheless have similar symptoms. Because symptoms may be similar in one genetic type of cancer and another, it is important to know everything possible about cancer genes and their interactions in prescribing an effective treatment. Physicians will be able to use a molecular/genomic test to help select the most effective drug with the minimum number of side effects. As a result, this approach should benefit the patient with more customized care, reduced length of illness, and, ultimately, a better and longer life.
Approximately 2.2 million Americans are admitted to hospitals every year as a result of adverse side effects from drugs; more than 100,000 die annually from these adverse (and often unpredictable) effects. For instance, some cause liver damage, while others are harmful to the kidneys. Organ-specific gene expression profiles for drugs already available will enable researchers to study the toxicity of new drug compounds with more certainty.
In addition, gene expression data, combined with polymorphism information related to metabolic pathways, will provide important indications of the way an individual patient will react to drugs of various dosage levels, thereby significantly reducing the unwanted side effects of therapy. |
SOURCE: Celera Genomics |
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DATA:
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How Celera Genomics unraveled the 3.5 billion letters of the human genetic code.Every cell of every living organism contains genetic material made up of the compounds adenine, thymine, cytosine and guanine, represented as A, T, C and G. The precise order of these letters regulates every aspect of the organism's life from conception to death. Here is how Celera Genomics unraveled the 3.5 billion letters of the human genetic code.
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1. Sperm and blood cells containing genetic material are collected from volunteer donors. |
| 2. DNA is extracted from cells and chopped up into tiny bits. |
3. Billions of copies of each DNA fragment are needed to permit efficient machine analysis. So the fragments are spliced into bacteria that work like living copy machines. Each germ produces billions of offspring, each containing copies of the original DNA fragment. |
| 4. The human DNA is extracted and treated with special dyes that make each unit of genetic information glow a particular color under laser light. |
5. Hundreds of machines with robot arms pump DNA fragments into thin glass tubes. The negatively charged DNA is pulled toward a positive charge at the end of each tube. As DNA fragments emerge, a laser beam and camera record the dye color. Scientists now have the sequence for one small DNA fragment.
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| 6. Running quadrillions of calculations, computers match each DNA fragment against every other to find overlapping ends. Ultimately, all fragments are reassembled into a complete genetic sequence. |
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