Genetic Engineering And Biotechnology Research Essay
A. Recombinant DNA Technology
Recombinant DNA is DNA that has been artificially created. It involves taking one piece of DNA and combining it with another piece of DNA. By combining two or more strands of DNA, scientists form a new strand of DNA.
Gene Transfer using Plasmids
• In order to transfer one strand of DNA from one species to another, a host cell is needed. E. coli is often used as a host cell for gene transfer because it not only has circular DNA, but also a smaller ring of independent, self-replicating DNA called a plasmid.
• Plasmids are removed from a cell and broken apart using a restriction endonuclease. Restriction endonucleases are enzymes that have the property to cut the desired DNA molecules at their individual base sequences.
• Restriction endonucleases are used for gene transfer because they cut the two strands of DNA at different parts, leaving behind single stranded fragments that have ‘sticky ends’. These ends can rejoin by hydrogen bonding between the complementary bases. After that DNA ligase (an enzyme) is added to form sugar-phosphate bonds and seal the plasmid.
• A restriction endonuclease can cut DNA molecules in any species. Therefore, a DNA fragments from one species can be inserted into the plasmid of another species that has been removed from the cell and broken apart. Then the recombinant plasmid is put back into the host cell that duplicates through cell divisions.…