07-27-2010, 10:13 PM
DNA or deoxyribonucleic acid is the hereditary material in humans as well as plants and animals. Every cell in the body has the same structure and function of DNA. It is found in the cell’s nucleus. Mitochondria are cell organelles which contain the small amount of DNA. There are four nucleotide bases which make the structure of DNA that are adenine, guanine, cytosine and thymine. These bases are actually the genetic information stored in the DNA molecules in the form of codes. There are almost 3 billion bases and all the people have 99% similarity with each other in their bases.
Recombinant DNA
Following are three methods through which recombinant DNA is made.
Transformation
- First the piece of DNA is selected which is to be inserted into the vector or plasmid.
- Isolated DNA piece is cut by using restriction enzymes.
- The cut piece is inserted into the vector where it attaches to the genetic material already present in the vector with the enzyme called DNA ligase .
- A genetic marker is used for the identification of recombinant DNA. Usually an antibiotic marker is used.
- This process of inserting vector into the host cell is called as transformation.
During the process of transformation, usually E. coli acts as a host cell. When a foreign gene is inserted into this vector, it is prepared before the insertion so that it accepts the gene. To keep the foreign gene or DNA different from the host cell’s genome, markers, color changes or some other characteristics are used.
Non-bacterial Transformation
This process of synthesis of recombinant DNA is different from the transformation process in the sense that it does not use bacteria as a host for the foreign DNA but other sources are used. For example, DNA microinjection is used in which cell is inserted into the nucleus of the recipient cell directly. Bioballistic is another method in which silver particles are used with the help of gene gun to bombard the recombinant DNA into the recipient cell.
Phage
In this process, a vector is used instead of bacteria as host cell. Phage is a type of virus which acts as a host cell for carrying recombinant DNA. Scientists inactivate the function of virus itself so that when it enters the body, it only inserts the recombinant DNA and does not cause any infections.
Function of Recombinant DNA
When the recombinant DNA enters the host cell, the host cell starts expressing the proteins present in the rDNA. If the expression factors are added along with the rDNA then host cell will be able to produce significant amount of proteins. Expression of the protein will not appear until there are some signals in the host cells. There are specific signals for every species of bacteria for example; E. coli does not get the signals of human terminators and promoters.
Importance of Recombinant DNA
Recombinant DNA is very helpful in techniques like gene therapy. It is helpful in curing different diseases like cancer. Healthy genes are inserted in the body and they replace the defected genes. Some other important features of recombinant DNA are that it can give better yield of crops. Disease like sickle cell anemia and hemophilia can be treated with recombinant DNA because it produces clotting factors. Scientists have successfully produced insulin with the help of recombinant DNA. Pharmaceutical industry has taken advantage of rDNA by making drugs. Recombinant DNA has enabled plants to make their own insecticides.
Recombinant DNA
Following are three methods through which recombinant DNA is made.
Transformation
- First the piece of DNA is selected which is to be inserted into the vector or plasmid.
- Isolated DNA piece is cut by using restriction enzymes.
- The cut piece is inserted into the vector where it attaches to the genetic material already present in the vector with the enzyme called DNA ligase .
- A genetic marker is used for the identification of recombinant DNA. Usually an antibiotic marker is used.
- This process of inserting vector into the host cell is called as transformation.
During the process of transformation, usually E. coli acts as a host cell. When a foreign gene is inserted into this vector, it is prepared before the insertion so that it accepts the gene. To keep the foreign gene or DNA different from the host cell’s genome, markers, color changes or some other characteristics are used.
Non-bacterial Transformation
This process of synthesis of recombinant DNA is different from the transformation process in the sense that it does not use bacteria as a host for the foreign DNA but other sources are used. For example, DNA microinjection is used in which cell is inserted into the nucleus of the recipient cell directly. Bioballistic is another method in which silver particles are used with the help of gene gun to bombard the recombinant DNA into the recipient cell.
Phage
In this process, a vector is used instead of bacteria as host cell. Phage is a type of virus which acts as a host cell for carrying recombinant DNA. Scientists inactivate the function of virus itself so that when it enters the body, it only inserts the recombinant DNA and does not cause any infections.
Function of Recombinant DNA
When the recombinant DNA enters the host cell, the host cell starts expressing the proteins present in the rDNA. If the expression factors are added along with the rDNA then host cell will be able to produce significant amount of proteins. Expression of the protein will not appear until there are some signals in the host cells. There are specific signals for every species of bacteria for example; E. coli does not get the signals of human terminators and promoters.
Importance of Recombinant DNA
Recombinant DNA is very helpful in techniques like gene therapy. It is helpful in curing different diseases like cancer. Healthy genes are inserted in the body and they replace the defected genes. Some other important features of recombinant DNA are that it can give better yield of crops. Disease like sickle cell anemia and hemophilia can be treated with recombinant DNA because it produces clotting factors. Scientists have successfully produced insulin with the help of recombinant DNA. Pharmaceutical industry has taken advantage of rDNA by making drugs. Recombinant DNA has enabled plants to make their own insecticides.
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