Genetic engineering involves the alteration of an organism's genetic, or hereditary, material to eliminate undesirable characteristics or to produce desirable new ones. Genetic engineering is used to increase plant and animal food production; to diagnose disease, improve medical treatment, and produce vaccines and other useful drugs; and to help dispose of industrial wastes. Included in genetic engineering techniques are the selective breeding of
plants and animals, hybridization (reproduction between different strains and species), and recombinant deoxyribonucleic acid (DNA) technology. Genetic engineering enables scientists to produce clones of cells or organisms that contain the same genes. The basic steps are: 1) Scientists use restriction enzymes to isolate a segment of deoxyribonucleic acid (DNA) that contains a gene of interest — for example, the gene regulating insulin production. 2) A plasmid extracted from a bacterium and treated with the same restriction enzyme can hybridize with this fragment's “sticky” ends of complementary DNA. 3) The hybrid plasmid is reincorporated into the bacterium, where it replicates as part of the cell's DNA. 4) A large number of identical daughter cells (clones) can be cultured and their gene products extracted for human use.
In 1977 scientists successfully manipulated bacteria to produce a human protein. That same year American molecular biologist Walter Gilbert found a way to accelerate dramatically the laborious task of sequencing the chemicals that make up a strand of genetic material. He shared the 1980 Nobel Prize in chemistry for this achievement. In a 1980 Scientific American article, Gilbert and American molecular biologist Lydia Villa-Komaroff describe basic biotechnology techniques and their laboratory's success in producing rat insulin with genetically engineered bacteria. Human insulin was first produced in the lab using recombinant (genetically engineered) bacteria in 1978, and five years later recombinant human insulin, used to treat diabetes mellitus, became the first biopharmaceutical on the market.
The first genetic engineering technique, still used today, was the selective breeding of plants and animals, usually for increased food production. In selective breeding, only those plants or animals with desirable characteristics are chosen for further breeding. Corn has been selectively bred for increased kernel size and number and for nutritional content for about 7,000 years. More recently, selective breeding of wheat and rice to produce higher yields has helped supply the world's ever-increasing need for food.
If you want to know more about genetic engineering, please browse the website www.genengnews.com.
2. gene therapy Gene therapy is experimental medical treatment that manipulates a gene or genes within cells in order to produce proteins that change the function of those cells. Gene therapy originated in efforts to treat and cure some of the more than 4,000 known genetic disorders, most of which lack an effective therapy. In the United States 1 infant in every 100 is born with a serious disorder caused by a defect in 1 or more of the estimated 31,000 genes found in the human body. Thousands of children and adolescents die from these diseases every year, and tens of thousands suffer lifelong disability. Although gene therapy is not an approved medical therapy to treat disease, over 400 clinical trials, experiments testing the safety and efficacy of this method on humans, have been conducted in the United States. Scientists expect that within the first decades of the 21st century, gene therapy will offer unprecedented opportunities to treat, cure, and ultimately prevent a vast range of diseases.
Gene therapy may someday be able to cure hereditary diseases, such as hemophilia and cystic fibrosis, which are caused by missing or defective genes. In one type of gene therapy, genetically engineered viruses are used to insert new, functioning genes into the cells of people who are unable to produce certain hormones or proteins necessary for the body to function normally.
The original goal of gene therapy was to substitute a healthy gene for a defective one, or to repair a faulty gene, thereby eliminating symptoms of disease. But researchers have moved beyond inherited genetic disorders to treat other kinds of diseases. Today, nearly 75 percent of all clinical trials involving gene therapy are aimed at treatments for cancer and acquired immunodeficiency syndrome (AIDS). Cancer begins in genes and may be caused by an inherited defect or a mutation (permanent alteration to a gene) that causes a cell to malfunction. AIDS is caused by a virus that disrupts the genetic material of immune cells. Other new gene therapy projects are targeted at conditions such as heart disease, diabetes mellitus, arthritis, and Alzheimer's disease, all of which involve genetic susceptibility to illness. Gene therapists hope to reduce or eliminate this susceptibility. Eventually, gene therapy might help older people to regain strength in withered muscles and density in thinned bones, and to increase pumping power in their aging hearts. Some researchers predict that in the distant future the technology could be used to eliminate genetic defects from families or even to produce “designer babies” with more muscle strength, higher intelligence, sweeter dispositions, or whatever traits parents desire.
While gene therapy offers seemingly limitless possibilities, in fact, researchers have been thwarted by many technical problems. There has only been one truly successful clinical trial using gene therapy — in April 2000 French researchers reported the successful use of gene therapy to treat two female infants with human severe combined immunodeficiency disease (SCID), a deadly inherited disease that impairs the immune system. But most clinical trials of gene therapy have not resulted in enough improvement in the patient's underlying condition to consider it an unqualified success and to justify treating large numbers of people. The extraordinary potential of gene therapy has also raised alarms among critics who warn that the technology could go too far. They note, for example, that gene therapy could offer wealthy families opportunities for genetic enhancement unavailable to the poor. More troubling still for some critics is gene therapy's potential to narrow the human gene pool, producing unknown, and possibly harmful, consequences.
To find further information about gene therapy, please visit the websites www.ornl.gov/hgmis/medicine/genetherapy.html, www.genetherapysystems.com and www.humangenetherapy.com.
3. Yellowstone National Park
Yellowstone National Park was established in 1872. Located in northwestern Wyoming and extending into Montana and Idaho, the park is known for its spectacular geysers, hot springs, canyons, and fossil forests. Yellowstone was the world's first national park. Native American groups lived in the area of Yellowstone for thousands of years. The name Yellowstone is thought to come from a translation of the Native American Minnetaree word mi tsi a-da-zi, for the yellow cliffs along the Yellowstone River. The first explorer to visit the Yellowstone area was John Colter in 1807, who had left the Lewis and Clark Expedition the previous year to explore the region. Explorations conducted by David Folsom, Charles Cook, and William Peterson in 1869, and by Henry Washburn, Nathaniel Langford, and Gustavus Doane in 1870 helped publicize the beauty of the area. Depictions of the region created during an expedition in 1871 by photographer William Henry Jackson and artist Thomas Moran convinced the American public and the United States government to preserve the area. President Ulysses S. Grant signed the bill creating the national park in 1872. An earthquake in 1959 with a magnitude of 7. 5 on the Richter scale caused major disturbances throughout the park. In August and September 1988, a series of fires, fueled by dry and windy summer weather, burned more than 35 percent of the park.
Straddling the Yellowstone River and stretching across three states, Yellowstone National Park is, at 898,714 hectares (2. 2 million acres), larger than the states of Delaware and Rhode Island combined. Although the United States National Park Service now administers over 350 national parks, Yellowstone was the nation's and the world's first national park. Established in 1872, the park draws millions of tourists a year to its mountain ranges, canyons, forests, and famous geysers. Over the years, human activity has effected change in the once pristine refuge.
Located in the central Rocky Mountains, Yellowstone National Park is a broad volcanic plateau surrounded by mountain ranges. The park has an average elevation of 2,300 m (7,500 ft). The Gallatin Range in the northwest section of the park reaches an elevation of 3,350 m (10,992 ft) at Electric Peak. The Washburn Range, just east of the Gallatin Range, features Mount Washburn, which offers outstanding views of the park from its height of 3,122 m (10,243 ft). The Absaroka Range extending along the eastern side of the park includes Eagle Peak, the park's highest point at 3,462 m (11,358 ft).
For further information about Yellowstone National Park, please visit the websites www.nps.gov/yell and www.yellowstone.net.
