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Chapter 14 : Recombinant Paper Plasmids
Some of the most important techniques used in biotechnology today involve making recombinant DNA molecules. Recombinant DNA molecules are pieces of DNA that have been reassembled from pieces taken from more than one source of DNA. Plasmids are copied by the cell’s DNA replication enzymes because they contain a special sequence of DNA bases called an origin of replication. Plasmids often contain genes for resistance to antibiotics. Plasmids carrying genes for ampicillin and kanamycin resistance are assembled and the two plasmids are recombined. The plasmid with ampicillin resistance is called as pAMP, the plasmid with kanamycin resistance as pKAN, and the recombinant plasmid as pAMP/KAN. Scientists place real recombinant plasmids back into bacteria, where they are replicated. The multiplying bacteria, carrying the recombinant plasmid, generate millions of copies of the recombinant DNA molecule and the proteins it encodes. New copies of the plasmid are synthesized by the cell’s DNA replication enzymes and passed to daughter cells as the bacteria multiply.