Genetic engineering means deliberately altering the genes of plants and animals to give them slightly different life instructions.
Genes are found in every living cell on special molecules called DNA (deoxyribonucleic acid). Engineering genes means changing the DNA.
Scientists alter genes by snipping them from the DNA of one organism and inserting them into the DNA of another. This is called gene splicing. The altered DNA is called recombinant DNA.
Genes are cut from DNA using biological scissors called restriction enzymes. They are spliced into DNA using biological glue called DNA ligase.
Once a cell has its new DNA, every time the cell reproduces the new cells will have the same altered DNA.
By splicing new genes into the DNA of bacteria, scientists can turn them into factories for making valuable natural chemicals. One protein made like this is interferon, a natural body chemical which protects humans against certain viruses.
Scientists are now finding ways of genetically modifying food crop, to make them resist pests or frosts, for instance. The first GM food was the `Flavr Savr’ tomato, created by the US company Calgene in 1994. FASCINATING FACT In 1999, scientists worked out the complete gene sequence for a multicelled organism – allowing them to create a new organism artificially.
Genetic engineering may be used to make animals grow faster.
Gene therapy means altering the genes to cure diseases that are inherited from parents or caused by faulty genes.
Cloning means creating an organism with exactly the same genes as another. Normally, new life grows from sex cells – cells from both parents – in which genes are mixed. Cloning takes DNA from any body cell and uses it to grow a new life. Since the new life has the same genes as the donor of the DNA, it is a perfect living replica.