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					genetic engineering

                                                                                                                                                                                                                                                                                                                 more information:
                  new horizons in medicine
Since genetic engineering (also known as                                                    The basic steps in the genetic engineering of a bacterium                                                                                             Gene therapy
                                                                                            The required gene is EITHER cut from the DNA of an organism
recombinant DNA technology or genetic
                                                                                            using enzymes called restriction endonucleases which                                                                                                  Gene therapy is still in it’s very early stages. It involves
modification) was first developed in the 1970s                                              leave the gene with overlapping sections called sticky ends...     ...OR   ...synthesised specifically                                                modifying human DNA either to repair it or to replace
                                                                                                                                                                                                                                                  a faulty gene. The idea of gene therapy is
scientists have discovered more and more                                                                                                                                                                                                          to overcome the effects of a mutation which causes
                                                                                                                                                                 Gene with
ways in which this new technology can be                                                                  Required gene                                                                                                                           a genetic disease. Cystic fibrosis is the best known
                                                                                                                                                                 sticky ends                                                                      disease where gene therapy has been tried.
used in human medicine. The same basic                                                                                                                                                                                                            There have been no long term successes – yet!

technique is used in modifying the genetic                                                                                                                             Bacterial
                                                                                                                  Gene with                                            plasmid
material of bacteria, plants and animals.
                                                                                                                  sticky ends

                                                  Pharming                                    A vector molecule (often a bacterial
                                                                                              plasmid, the small circular strand of DNA
                                                  Microorganisms, animals and plants          found in bacteria) is opened up, also                          Marker
                                                  can be genetically modified to                                                                             gene
                                                  produce medically useful products.
                                                                                              using restriction enzymes and leaving
                                                                                              sticky ends.
                                                  These transgenic organisms are
                                                                                                                                                                                                                                                  Some vaccines are very dangerous to make using
                                                  already used regularly to produce
                                                                                                                                                                                                                                                  conventional methods. Genetically engineered
                                                  substances such as human insulin,
                                                                                                                                                                                                                                                  microbes can be used to produce the antigens
                                                  human growth hormone and blood
                                                                                                                                                                                                                                                  needed in a safe and controllable way. The use of
                                                  clotting factors for haemophiliacs.
                                                                                                                                                                                                                                                  genetically modified yeast cells to produce a
                                                                                                                                                                                                                                                  vaccine against the hepatitis B virus has been a
                                                                                                             The new gene is annealed (joined                                                                                                     major success story.
                                                                                                             into the plasmid using the sticky ends)
                                                                                                             and sealed in place using another
                                                                                                             enzyme known as DNA ligase.                                                                                           ett

                                                  Diagnostic                                                                                                                                               me


                                                  tests and
                                                  targeted drugs
                                                  Genetic engineering is opening up
                                                  opportunities to produce very                                                                                                          Bacterium                                                Xenotransplantation
                                                  specific and sensitive diagnostic tests
                                                  for many diseases, using engineered                                                                     Plasmid with                                                                            The DNA of pigs has been modified using
                                                                                                                                                                                                                                                  recombinant DNA technology so their cells develop
                                                  proteins. This new technology is also     The recombinant plasmid is                                    engineered gene
                                                                                                                                                                                                                                                  without certain genes which trigger the human
                                                  opening up novel ways of delivering       inserted into a bacterial cell in a
                                                                                                                                                                                                                                                  immune response. The hope is that these genetically
                                                  medicines to specific targets.            process known as transformation.                                   Bacterial
                                                                                                                                                                                                                                                  modified organs might be accepted by a human
                                                                                            It is then replicated whenever the
                                                                                                                                                               DNA                                                                                recipient. In time pigs may even be given genes
                                                                                            bacterial cell replicates, and brings
                                                                                                                                                                                                                                                  which code for human antigens – but there are
                                        n   tre                                             about the manufacture of a new
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                           Lib netic                                                                                                                                                                                                              many ethical and safety questions still to be
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           We ssex                                                                                                                                                                                                                                answered in this area of genetic engineering.
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Description: Genetic engineering, also known as gene-splicing techniques and DNA recombinant technology, is based on the theory of molecular genetics, molecular biology and microbiology and modern methods as a means of genes from different sources according to pre-designed blueprint for building hybrids in vitro DNA molecules into living cells and then to change the genetic characteristics of the original biological, access to new varieties, production of new products.