What is oligonucleotide?

oligonucleotide is a short chain of DNA or RNA molecules that has many uses in molecular biology and medicine. It is used as a probe for screening for diseases, viral infections and to identify genes in molecular biology experiments. It is also used as a primer in the type of DNA sequencing.

To understand oligonucleotide, it helps to understand the structure of DNA. DNA molecules are very long coils of two chains made of four different nucleotide basic units arranged in different orders. Each unit has an additional base that is bound, so each spring has the opposite set of foundations that bind it. These bases can form a large range of different combinations and is a combination of foundations that give a genetic code. DNA is transcribed to form Messenger RNA (MRNA), which is then translated for the purpose of Protein production.

oligonucleotides are identified by the length of the string. For example, oligonucleotide, which is a long ten nucleotide bases, would be called ten mers . They are generally synthesized chemically and the type of synthesis limits the chain length to less than 60 bases.

In the type of DNA sequencing known as dideoxy sequencing oligonucleotides are used as a primer, so an enzyme that causes DNA to have a template for work. A single -stranded DNA and oligonucleotide, which is complemented with a spring source, is used, is synthesized using an automated machine. DNA polymerase, which synthesizes DNA, continues to add primer and synthesizes the opposite DNA chain from it. This reaction produces two -fighted DNA.

Newer use of oligonucleotides as primers is in the polymerase chain reaction (PCR), which is used to amplification of small DNA fragments. This technique has highly practical uses, for example in forensic and paternity testing. He also revolutionized research in medicine and biological stories because it is often used in genetic experimentsican engineering.

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series of oligonucleotide probes is often used to isolation of gene library or complementary DNA (CDNA) genes. The CDNA libraries consist of a two -string DNA, in which one spring is derived from the MRNA chain and the other is complemented. Such libraries have the advantage that they do not have gaps that often occur in genes from higher organisms.

The structure of genes from many organisms is known as sequence projects and is publicly available. If a person wants to clone a gene from another organism, we see what is known about the gene in other organisms, and design probes based on common areas in these sequences. Scientists then have a synthesized range of oligonucleotide probes that take into account possible changes to common areas. They stand the library with these probes looking for oligonucleotides that bind. Many genes have been identified in this way.

Antisense oligonucleotide contains a single RNA or DNA string that is a supplement to the sequence of interest. AsE is cloned with a specific protein gene code, Antisense RNA is often used to block its expression by binding to MRNA to synthesize it. This allows scientists to determine the effects on the body when this protein does not mean. Antisense oligonucleotides also evolve as new types of drugs for blocking toxic RNA.

Microarray chips were another area in which oligonucleotides have great usefulness. These are glass slides or some other matrix, which have places containing thousands of different DNA probes - in this case made of oligonucleotides. They are a very effective way to test changes in a number of different genes at a time. DNA is tied to a compound that changes color or fluorescent lamps if it is bound by complementary DNA, so the stains change color if there is a reaction with a test DNA.

Some of the things that are used by oligonucleotide microchips to include screening for genetic disease. For example, there are small probes that represent a GE activityNů involved in breast cancer, brc1 and brc2 . It is possible to determine whether a woman has a mutation in one of these genes and further analyze it to see if she has a breast cancer predisposition.

There is a microchiproom called Virochip , which has probes for about 20,000 genes from different pathogenic viruses that have been seized. Body secretion, such as PLEGM, can be analyzed using a chip that can often identify what type of virus is infected. Identification of viral infections can be quite difficult because symptoms are often similar to different types of viruses.