| In the last half century, a scientific revolution has arisen with the potential to influence civilization like perhaps no other in history. Beginning in the 1950s, cytologists (cell biologists) began to separate individual chromosomes from a cell's genetic material to be analyzed under a microscope. This process, known as karyotyping, allowed genetecists to identify the characteristics of certain chromosome that appear in cases of genetic disease. In the late 1960s, researchers were first able to stain individual chromosomes in a human DNA strand. Early research that led to the discovery of the structure of DNA revealed the presence of the four nucleotide bases: Adenine, Cytosine, Guanine, and Thyamine. It was later found that the order of these bases is responsible for the formation of specific amino acids, which are the building blocks of enzymes and proteins. The type, order, and amount of proteins and enzymes made by a cell's DNA gives the cells their own unique characteristics and functions, which in turn give the entire organism its own set of unique characteristics and functions. |  |
The genetic sequence is passed on from generation to generation through the process of reproduction, and a inherent to the reproductive process are infrequent copying errors. Those errors (mutations) which are not fatal to the cell or the organism are passed on, leading to variations within a population. The earliest form of gene manipulation was selective breeding. In this process, desirable characteristics can be bred into a species by selecting parents with those characteristics. In the same process, undesirable characteristics can be bred out of a population. This process has been employed, intentionally or not, throughout the history of civilization. The outcome, however, is frequently inaccurate and to some extent unpredictable. In nature, spontaneous mutations in the genetic code occur randomly. In recent decades, however, the ability to cause and control the mutation of specific genes has been developed. Genes can now be taken from one species and inserted directly into the DNA of a different species. To date, most engineering has been done in the field of agriculture, to create plants and animals that are larger, healthier, heartier, and resistant to disease, drought, and predation. However, the effects of such alterations are bound to have unintended side effects. Mass manufacturing of genetically-engineered crops has already greatly reduced the diversity of many harvested foods, leaving the food supply highly susceptible to plagues, which may wipe out field after field of crops, none of which have a naturally-occurring genetic defense.
from Consumer Reports Sept 1998, p 67 | With the rapid increase in genetic research in the field of medicine came the Human Genome Project, a bold effort to map the complete sequence of genes in the human genome. Mapping the genome will have huge implications in the fields of medicine and heredity as scientists identify the sections that code for health factors, disease, and behavioral tendencies. While there are numerous medical benefits to this ability, there are also ethical considerations. An individual's genetic makeup could be used as a basis for employment discrimination or denial of medical coverage. It could be used to select characteristics of future children or to decide whether a fetus is worth bringing to full term. As this information becomes more readily available, privacy becaomes an issue. Who has a right to know your genetic information or to alter your genetic code? Cloning is yet another face of genetic engineering that has been seen frequently in the popular media. Rather than maintaining characteristics through reproduction, cloning allows the entire genome of an adult to be inserted into an egg, creating an embryo with the same genetic code, which will grow into an adult genetically identical to the original. Many animal species have been successfully cloned to date, and it remains only a matter of time before a human is successfully cloned. Cloning technology has been proposed as a method of reviving extinct or nearly-extinct species, of growing replacement body parts to extend life, or of bringing back lost loved ones.
Advances in biotechnology continually confront society with new moral and ethical situations that come in confilct with the rights and desires of individuals, and we as society are ill-equipped to deal with these conflicts . Where does the responsibility lie in making decisions on issues of genetic manipulation - with the government, with the scientific and medical community, or with individual citizens? This week you will consider some of these issues. Where should the lines be drawn and who should draw them? |
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