Recombinant DNA
DEFINITION;
Recombinant DNA is made by combining DNA from two or more sources (organisms)
DNA is the main genetic material in all organisms, and an enzyme was discovered to cut this genetic material into small pieces called restriction endonuclease. It acts like chemical scissors.
By combining two such different DNA fragments, a new DNA is formed. It is called recombinant DNA and the method used to make such DNA is called recombinant DNA technology.
Recombinant DNA (r-DNA) is actually produced by the mutual covalent linkage of the DNA of a different organism and that of a carrier DNA.
FORMATION OF RECOMBINANT DNA ;๐
CARRIER OR VECTOR [ plasmids ]
It is found in the cytoplasm of bacteria. Are small, spherical, extracellular chromosomal DNA. It is the carrier molecule of DNA.
FORMATION OF COMPLEMENTARY DNA
[ Construction of complementary DNA by isolating the genes of a eukaryotic cell ]
( c - DNA )
Complementary DNA (c - DNA) is synthesized by its m-RNA to obtain a gene or DNA from a eukaryotic cell.
In this method, the m-RNA of a specific gene (which carries the message of specific protein synthesis) is prepared by culture medium [in which c-DNA is produced by its reverse transcription in the presence of a reverse transcriptase enzyme.]
CONSTRUCTION OF GENE - BEARING VECTOR
(a) Both ends of the synthesized cDNA are converted into viscous ends. Some deoxyribonucleotides are added at both ends of the cDNA with the help of a terminal transferase enzyme at 3 '.
(b) Viscous ends are formed by adding polynucleotides from both 3 'ends of plasmid DNA with the help of a terminal transferase enzyme.
(c) The viscous ends of the c-DNA are placed in contact with the viscous ends of the carrier DNA, forming pairs of bases in them.
With the help of enzyme DNA linkage, both pieces of DNA are covalently formed and r-DNA is formed.
TRANSFORMATION OF RECOMBINANT DNA
Under transformation, an independent r-DNA is transferred to a bacterial cell.
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