Genetic technology is being used today in agriculture and forestry to improve plants; increasing disease resistance, increasing the yields of crops, and adapting nonnative plants to a new environment where it has been determined they will be of benefit to the ecosystem.
Animal breeders have been using genetic principles for many years to develop characteristics within a species that they feel are desirable. This has improved the quality and quantity of food production in much of the world. A review of the many and varied dog breeds that have been developed over the years is a very good example of the diversity that can occur within a species.
New technology involving recombinant DNA has proven beneficial in medicine.
Hemophilia is a disorder of the blood that interferes with clotting. Some victims of this disease in the past bled to death after very minor injuries. Hemophilia is an X-linked genetic disorder. The trait is not passed from father to son because fathers only pass on Y chromosomes to their sons. It is rarely manifested in females because they have a second X chromosome which has a normal gene. Females become the carriers of this recessive gene, with a fifty percent risk of passing it to their sons and daughters.
In more recent years, the clotting factor in blood has been isolated and it was possible for a person with hemophilia to survive with transfusions of this clotting factor extracted from normal human blood. However, the recent emergence of AIDS has given these patients a new possible death sentence. Some were transfused with contaminated blood before testing was available; and,even with new screening methods, it is questioned whether all blood supplies are safe. The recent death of Ryan White, a teenager who had hemophilia and who acquired AIDS in this way, captured the sympathetic attention of the country and beyond.
Recombinant DNA technology has made it possible to produce bacteria with a human gene for manufacturing the clotting factor needed by patients affected by hemophilia. This clotting factor is harvested in vats where great quantities of genetically altered bacteria work to produce clotting factor that has never been in the body of another human being; therefore, it is completely disease free.
Bacteria have also been altered to produce human growth hormone which was previously available only by processing material from the pituitary glands of dead humans. The problems of disease transmission were similar to that faced by hemophiliacs.
Insulin to alleviate diabetes can also be produced by genetically altered bacteria.
Expanding knowledge of genetic factors as the cause of many diseases and handicapping conditions have led to test procedures that can identify carriers of many of these conditions. There are also tests that can be done early in pregnancy to determine if the fetus is affected by certain deleterious genetic conditions.
A genetic counselor works with prospective parents to help them make difficult decisions when faced with the probability of a genetic disorder in their children. Genetic counselors also act as patient advocates for people with genetic disorders and do community outreach in genetic education.
It is possible to arrange for a genetic counselor or a physician specializing in medical genetics to work with you as a resource person when dealing with genetic topics in the classroom by calling The Department of Human Genetics of Yale School of Medicine. Dr. Seashore may even be able to arrange for a laboratory visit for some groups.
A classroom visit by a plant geneticist can be arranged by calling the Biochemistry and Genetics Department of the Connecticut Agriculture Experiment Station.
Because of the rapid development of breakthroughs in the science of genetics and the frequency with which they are reported, students should be encouraged to assist in accumulating articles for discussion and display in the classroom.