Modern biotechnology techniques are based only on the isolation and manipulation of DNA these days. These techniques made it possible to detect diseases and make certain precautionary measures to protect people from these diseases. Some of the techniques are described in this article.
DNA isolation techniques totally depend on the experimental organism, but somehow these techniques have following characteristics.
1) A treatment for opening the cells and releasing their DNA
2) Method for inactivating and removing the enzymes which degrade the DNA
3) Method to separate the DNA from proteins and other molecules which contaminate the DNA
There are many cheap laboratory exercises for the isolation of DNA which are also very simple. DNA is usually taken from onion, bacteria and other organisms. Heat and detergent is used to isolate the DNA. These methods break open the cell and inactivate the enzymes which degrade DNA. DNA is separated from other contaminants by using alcohol precipitation. The method of DNA isolation is more reproducible is isolation the DNA from bacteria16. There are many companies who sell kits to for DNA isolation. DNA is isolated from human body cells to detect genetic diseases in the newborn child, to analyze the forensic evidence and to study genes which are involved in causing cancer.
Over the past couple of decades biotechnologists have succeeded in developing DNA transfer techniques. It is the only the DNA which is required for the transformation. To get the DNA, in most cases tissues are exposed to stresses which enable the plasma membrane to rupture and in other cases cell wall of the plants is used. Through this process some of the cells will contain the foreign DNA in their genome. This foreign DNA is helpful to make useful products and has been used in pharmaceuticals such as human insulin.
Restriction Enzyme Digestion and Analysis:-
Restriction enzymes are actually the proteins. They cut the sequences of bases of DNA at specific places. Biotechnologists are able to reproduce cut DNA molecules into small well defined fragments through these enzymes. In biotechnology, restriction enzymes are used to make and analyze new DNA molecules. Agarose gel electrophoresis is the technique through which biotechnologists are able to make new DNA molecules. Agarose gel makes new DNA molecules through following methods
1) Chains of sugars make agarose.
2) DNA is moved in the agarose gel through electric current and this current cuts them into smaller pieces according to their size.
3) Special kind of dye makes possible the identification of small DNA molecules in the gel.
Polymerase chain reaction:-
Polymerase chain reaction or PCR is a common technique in biotechnology. This technique is used for producing multiple copies of short DNA molecules. PCR runs through following process.
1) DNA molecule that will act as a template in the reaction
2) Short and single stranded DNA molecules which are called as primers. Primers are the starting points for making new DNA molecule.
3) An enzyme is needed which makes DNA
4) Nucleotides which are the building blocks of DNA
5) Thermal cycler, a machine, which subjects the reaction mixture to varying temperatures repeatedly.
DNA sequencing is the most important thing in the human genome project. Many biotechnology techniques are dependent on this method. To determine the exact order of bases in the DNA molecule is this technique's purpose. Nature of protein encoded in the DNA molecule can be determined through this technique.
It is a very useful technique of biotechnology. In this technique, expression of many genes can be analyzed simultaneously. Microarrays can be made on a glass slide or a chip and they contain hundreds and thousands of parts of genes in a small section of the slide. Expressed genes can be isolated from the cells and then are detected. This detection shows that which DNAs bind to which genes and are taken from which cells.
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