The benefits of human genetic engineering can be found in the headlines nearly every day. With the successful cloning of mammals and the completion of the Human Genome Project, scientists all over the world are aggressively researching the many different facets of human genetic engineering. These continuing breakthroughs have allowed science to more deeply understand DNA and its role in medicine, pharmacology, reproductive technology, and countless other fields. The most promising benefit of human genetic engineering is gene therapy.
Gene therapy is the medical treatment of a disease by repairing or replacing defective genes or introducing therapeutic genes to fight the disease. Over the past ten years, certain autoimmune diseases and heart disease have been treated with gene therapy. Many diseases, such as Huntington’s disease, ALS (Lou Gehrig’s disease), and cystic fibrosis are caused by a defective gene. The hope is that soon, through genetic engineering, a cure can be found for these diseases by either inserting a corrected gene, modifying the defective gene, or even performing genetic surgery.
Eventually the hope is to completely eliminate certain genetic diseases as well as treat non-genetic diseases with an appropriate gene therapy. Currently, many pregnant women elect to have their fetuses screened for genetic defects. The results of these screenings can allow the parents and their physician to prepare for the arrival of a child who may have special needs before, during, and after delivery. One possible future benefit of human genetic engineering is that, with gene therapy, a fetus w/ a genetic defect could be treated and even cured before it is born.
There is also current research into gene therapy for embryos before they are implanted into the mother through in-vitro fertilization. Another benefit of genetic engineering is the creation pharmaceutical products that are superior to their predecessors. These new pharmaceuticals are created through cloning certain genes. Currently on the market are bio-engineered insulin (which was previously obtained from sheep or cows) and human growth hormone (which in the past was obtained from cadavers) as well as bio-engineered hormones and blood clotting factors.
The hope in the future is to be able to create plants or fruits that contain a certain drug by manipulating their genes in the laboratory. The field of human genetic engineering is growing and changing at a tremendous pace. With these changes come several benefits and risks. These benefits and risks must be weighed in light of their moral, spiritual, legal, and ethical perspectives. The potential power of human genetic engineering comes with great responsibility. Disease and Medicine.
Genetic engineering has been used in the field of medicine for many purposes regarding the control and improvement of health. The process has been used to correct inherited genetic defects causing disease (gene therapy), to counter effects of genetic mutations, to produce various pharniaceutical products (Levine). Gene therapy is the use of genetic engineering techniques in the treatment of a genetic disorder or chronic disease. In 1990, a four-year-old girl received genie therapy treatment for adenosine deaminase (ADA) deficiency, an ordinarily fatal inherited disease of the immune system.
Because of this genetic defect, the girl was susceptible to recurrent life-threatening infections. Doctors removed white blood cells from the child’s body, let the cells grow in the lab, used a genetically modified virus to carry a normal ADA gene into her inimune cells, and then infused the genetically modified blood cells back into the patient’s bloodstream. The inserted ADA gene then programmed the cells to produce the missing ADA enzyme, which led to normal immune function iii those cells.
This treatment temporarily helped her to develop resistance to infection, and must be repeated periodically (Donnelly). Another important medical application of the recombinant- DNA procedure has been the production of vaccines against a number of diseases. Heretofore, vaccination against a disease has involved the injection of killed or weakened microorganisms into a person, with the subsequent production of antibodies by the individual’s immune system. This procedure has always carried the risk of there being live, virulent pathogens in the vaccine because of some error in the vaccine-producing process (Donnelly).
Through the recombinant-DNA procedure, it is now possible to transfer the genes that stimulate antibody formation to a harmless microorganism and use it as a vaccine against the particular disease. Vaccines have been successfully created using the harmless cowpox virus, the herpes simplex type I virus (cold sores), the influenza virus, and the hepatitis B virus through gene splicing (Blaese). Genetic engineering has also contributed several pharmaceutical products (besides vaccinations).
Recombinant-DNA procedures involving bacteria and donor DNA fragments have led to the increased availability of such medically important substances as insulin, interferon, and growth hormone (Rubenstein). These substances were previously available only in limited quantities from their primary sources. Insulin is a hormone produced in the pancreas that controls the absorption of glucose by cells. Diabetics lack the hormone or have decreased levels of it. Using recombinant-DNA techniques, scientists have created human insulin, which is artificially produced by gene-splicing methods in bacteria.
Heretofore, diabetic patients relied solely on insulin derived from the pancreases of animals to control glucose levels (Levine). The protein interferon is released into the bloodstream to induce healthy cells to manufacture an enzyme that counters a viral infection. It can also be effective against some forms of cancer, leukemia, genital warts, and the common cold. For many years, the supply of human interferon for research was limited by costly extraction techniques. l-Iowever, the protein became available in greater quantities through genetic engineering (Levine).
Генная инженерия человека В применении к человеку генная инженерия могла бы применяться для лечения наследственных болезней. Однако, технически, есть существенная разница между лечением самого пациента и изменением генома его потомков. Задача изменения генома взрослого человека несколько сложнее, чем выведение новых генноинженерных пород животных, поскольку в данном случае требуется изменить геном многочисленных клеток уже сформировавшегося организма, а не одной лишь яйцеклетки-зародыша. Для этого предлагается использовать вирусные частицы в качестве вектора.
Вирусные частицы способны проникать в значительный процент клеток взрослого человека, встраивая в них свою наследственную информацию; возможно контролируемое размножение вирусных частиц в организме. При этом для уменьшения побочных эффектов учёные стараются избегать внедрения генноинженерных ДНК в клетки половых органов, тем самым избегая воздействия на будущих потомков пациента. Также стоит отметить значительную критику этой технологии в СМИ: разработка генноинженерных вирусов воспринимается многими как угроза для всего человечества.
С помощью генотерапии в будущем возможно изменение генома человека. В настоящее время эффективные методы изменения генома человека находятся на стадии разработки и испытаний на приматах. Долгое время генетическая инженерия обезьян сталкивалась с серьёзными трудностями, однако в 2009 году эксперименты увенчались успехом: в журнале Natureпоявилась публикация об успешном применении генноинженерных вирусных векторов для исцеления взрослого самца обезьяны от дальтонизма.
[1] В этом же году дал потомство первый генетически модифицированный примат (выращенный из модифицированной яйцеклетки) — игрунка обыкновенная. [2] Хотя и в небольшом масштабе, генная инженерия уже используется для того, чтобы дать шанс забеременеть женщинам с некоторыми разновидностями бесплодия. [3] Для этого используют яйцеклетки здоровой женщины. Ребёнок в результате наследует генотип от одного отца и двух матерей.