2 An overview of the recombination process. (v) Selection of transformed host cells: Transformed cells (or recombinant cells) are those host cells which have taken up the recDNA molecule. Isolate gene of interest. That is, their appearance, behavior and metabolism are usually unchanged, and the only way to demonstrate the presence of recombinant sequences is to examine the DNA itself, typically using a polymerase chain reaction (PCR) test. Vector is taken up by cell.  It is one of two most widely used methods, along with polymerase chain reaction (PCR), used to direct the replication of any specific DNA sequence chosen by the experimentalist. One is that molecular cloning involves replication of the DNA within a living cell, while PCR replicates DNA in the test tube, free of living cells. Through this process, multiple copies of the gene of interest can be produced. Your email address will not be published. Foreign group roots for 'golden rice' in India", March 18, 2015, Vaccine information from Hepatitis B Foundation, reverse transcription polymerase chain reaction, HIV testing page from US Centers for Disease Control (CDC), "Recombinant protein expression in Escherichia coli: advances and challenges", "Promoters used to regulate gene expression", "Multi-compartment and multi-host vector suite for recombinant protein expression and purification", Food Biotechnology in the United States: Science, Regulation, and Issues, http://www.deccanherald.com/content/466247/foreign-group-roots-golden-rice.html, "Molecular basis for the herbicide resistance of Roundup Ready crops", "Biochemical method for inserting new genetic information into DNA of Simian Virus 40: Circular SV40 DNA molecules containing lambda phage genes and the galactose operon of Escherichia coli", "Cleavage of DNA by R 1 restriction endonuclease generates cohesive ends", "Construction of biologically functional bacterial plasmids in vitro", "Making dollars out of DNA. Werner Arber, Hamilton Smith, and Daniel Nathans shared the 1978 Nobel Prize in Physiology or Medicine for the discovery of restriction endonucleases which enhanced the techniques of rDNA technology. SELECTION – After the introduction of recombinant DNA into the host cells, it is essential to identify those cells which received rDNA molecule - screening (or) selection.  In 1980 Paul Berg, a professor in the Biochemistry Department at Stanford and an author on one of the first papers  was awarded the Nobel Prize in Chemistry for his work on nucleic acids "with particular regard to recombinant DNA". Selection of Transformants • In recombinant DNA technology, after introduction of recombinant DNA molecules into host cells, it is important to select the host cell that takes up the DNA construct (transformed cell) from those that do not • It can be done by selectable marker genes or reporter genes 2 3. The desired genes and the vectors are snipped by the same restriction enzymes to acquire the complementary sticky ends.  Significant exceptions exist, and are discussed below. It relies on the activity of β-galactosidase, an enzyme occurring in E. coli, which cleaves lactose into glucose and galactose.  The first publications describing the successful production and intracellular replication of recombinant DNA appeared in 1972 and 1973, from Stanford and UCSF. Grow cells containing vector with gene. For example, plant DNA may be joined to bacterial DNA, or human DNA may be joined with fungal DNA. Furthermore, there are concerns about the by-products in biopharmaceutical production, where recombinant DNA result in specific protein products.