More than 300,000 people in Germany suffer from diabetes. They need insulin, a hormone that is now produced by genetic engineering. Insulin is produced by the islets of Langerhans in the pancreas; it regulates sugar levels. If the hormone fails, this leads to the clinical picture of diabetes. Human insulin is the first drug to be produced by genetic engineering. For the past 15 years, it has been possible to produce the hormone, which is vital for diabetes sufferers, without having to extract it from the pancreas of slaughtered cattle or pigs. With the help of genetic engineering, the insulin blueprint was isolated from the cells of a human being and transferred into bacteria or yeasts. In large stirred tanks called fermenters, the microorganisms multiply and produce human insulin. Genetically engineered insulin is therefore absolutely free of pathogens from animals.
Difficult terms: gene, genome and genetic engineering.
The gene is the smallest unit of hereditary material (hereditary material is also called genome, i.e. the totality of all genes of an organism). Our genome contains between 30,000 and 40,000 genes; this is only about 300 genes more than the mouse and about twice as many as the fruit fly. About 9,000 human genes have already been identified. Genetic engineering encompasses all biological-technical processes that specifically alter the genetic material of a cell. The genetic information is stored in a gigantic molecule called deoxyribonucleic acid, for which the abbreviation DNA has become established in scientific usage (after the English term deoxyribonucleid acid); in German, it is otherwise referred to as DNA. The principle of genetic engineering: Sections of foreign DNA are introduced into the cell in order to bring about defined changes there. The well-known example is the drug human insulin produced in this way. In the genetic engineering of drugs, genes encoding therapeutically useful substances are transferred into cells that are as easy to cultivate as possible. Bacteria are ideal for this purpose, and more rarely yeast and mammalian cells. Genetic engineering has led to the development of new drugs such as human insulin, vaccines such as a treatment for hepatitis B, and diagnostics that are already in use worldwide. The approval of medicines produced with the aid of genetically modified organisms is regulated by the German Medicines Act and the German Animal Diseases Act. In addition, approval must be obtained in accordance with the Genetic Engineering Act. A major task of human genome research is to identify which genes are involved in the development of diseases and how. From this, scientists expect new concepts for the treatment of, for example, cardiovascular diseases, cancer, infectious diseases or diseases of the nervous system such as Parkinson’s disease, multiple sclerosis or Alzheimer’s disease.
The cloned sheep
Scottish scientists had succeeded in cloning a sheep in 1996 after removing the udder cell of a six-year-old sheep and inserting it into a previously enucleated egg. Dolly, the copy of another sheep, a miracle animal of science, the artificial product of flesh and blood was created from the genetic material of a body cell. But by mid-1999, it was noticed that Dolly’s genetic material looked unusually old – Dolly recently had to be euthanized. In cloning, however, no alteration of the genetic material takes place. Cloning is generally understood to be the artificial production of genetically identical living beings. Naturally genetically identical are, for example, all bacteria of a colony, in humans as a special case the identical twins.
Green genetic engineering
One area of application of so-called green genetic engineering is the production of food. Experts estimate that in Germany between 50 and 70 percent of our food has come into contact with genetic engineering. Starting with the enzymes and flavorings for our bread to anti-mud tomatoes, fungus-resistant red wine and performance-enhanced dairy cows, the spectrum of genetically modified products ranges. Research is being conducted into the use of genetic modifications, for example in biological pest control using genetically modified viruses, or to improve the quality of plant products, such as foodstuffs to improve shelf life, storage life, tolerance, nutritional value and taste. Not only animals and plants that serve directly as food are genetically modified, but also microorganisms that modify and refine food.Examples are the classic biological processes of beer and wine production or the ripening of cheese.
Hope gene therapy
Gene therapy uses any procedures that are employed to directly affect the genetic makeup for medical objectives. Gene therapy is already being used to treat hereditary diseases and cancer. There are great hopes here, though cautiously conceived over a long period of time, based on being able to use this understanding for better therapies of specific diseases. For example, if genes involved in the development of disease can be identified, ideally novel drugs could be developed that address the causes rather than just the symptoms.
Stem cell treatment in the womb
With stem cell treatment in the womb, California scientists have succeeded for the first time in curing an inherited disease before birth. Immunodeficiency is a disease in which newborns have no defenses against bacteria and therefore have to live in a germ-free tent for the first few years of their lives. For this purpose, healthy stem cells from the umbilical cord blood of another baby were injected into the unborn child before the 16th week of pregnancy. Stem cells are precursors of differentiated and thus specialized cells. In the bone marrow, for example, there are stem cells for cells found in the blood, such as lymphocytes. Stem cells of embryos can develop into a complete organism (then one speaks of totipotency). Stem cells of very low maturity are also found, albeit in very small numbers, in adult tissues such as liver, kidney, brain, or even in the umbilical cord blood of the newborn could serve as an alternative to embryonic stem cells – this is currently the subject of research. With stem cell transplantation, researchers succeeded for the first time in curing immunodeficiency already in the womb. Therefore, the injected healthy cells can take the place of the body’s own cells. When the healthy cells settle in the baby’s body, the missing enzyme is replaced and the defect is eliminated. The human genome has largely been decoded. This is considered a milestone in the history of mankind. But it is precisely here that new demands are being placed on science, politics and ethics. Ethics is challenged to show whether and how these findings can be used responsibly in areas as diverse as medicine and agriculture.