The Present and Future of Genetic Research
Genetics is the study of heredity and variation in organisms. Research in genetics usually is performed within a subset of organisms and not across all organisms. Genetic research is performed on humans, plants and animals. Many scientists study gene regulation and genetic influences on development and cancer.
History of Genetics
Gregor Mendel was the first to study the process of inheritance in the mid-nineteenth century. His work established the existence of discrete units upon which traits were inherited. These were later called genes.
In 1953 Francis Crick and James Watson determined the structure of DNA. The double helical structure and method of replication demonstrated how inheritance is accomplished.
Understanding the molecular basis of genetics was the key to DNA research. The production of proteins and amino acids from DNA and the cracking of the genetic code explained how DNA induces changes in cells.
Frederick Sanger developed a method of
sequencing DNA in 1977. In 1983 the polymerase chain reaction (PCR) was developed by Kary Mullis. This process allowed a stretch of DNA to be amplified and, therefore, studied. These developments made the sequencing of the human genome possible.
Research Organisms
Humans, of course, cannot be used as genetic research tools in experiments. Organisms are chosen, therefore, for their short generation times and easy genetic manipulation.
Popular model organisms include the bacterium Escherichia coli, the plant Arabidopsis thaliana, baker's yeast (Saccharomyces cerevisiae), the nematode Caenorhabditis elegans, the common fruit fly (Drosophila melanogaster) and the common house mouse (Mus musculus).
Genetic Research and Cures
One of the most important uses of genetics is studying the relationship between heredity and disease. Mutations in genes bring about changes in human health. These can either be hereditary or not.
Cancer is not inherited, but mutations in a gene can force the cell to become immortal. Medical genetics research tries to pull apart the chromosomes and unveil the mutations in DNA that bring about disease. This can be accomplished in many ways.
The HapMap Project is one such undertaking. Scientists map the location of haplotypes in relatively small populations to determine which genes are responsible for certain common diseases. Haplotypes are groupings of single mutations on an arm of a chromosome that are usually inherited together.
The genetic variations are easier to follow in small homogenous populations that do not normally marry outside their groups, like the Amish, the Yaruba of Nigeria and the Han Chinese. One criticism, however, is that this type of project can discover only genes responsible for rare diseases such as certain types of dwarfism.
Genetics may also be used to determine the cause of certain types of obesity. Some studies suggest that obesity susceptibility genes exist. The French pharmaceutical company Sanofi-Aventis plans to release the drug rimonabant to help people beat cravings for food.
Other studies have found that the protein Perilipin protects fat molecules from being broken down. Some people have versions of the gene that produces even stronger versions. Knowing these genetic variations can help to determine the diet regime that a patient must follow.
Autism can also be studied using genetic research. An autistic mouse model has been made by introducing a gene mutation. Mice with this mutation exhibit the same types of decreased social interactions and increased repetitive behavior that autistic people exhibit. This model will eventually help scientists study abnormal brain function in autistic patients. An autism model is likely to eventually help clinicians identify people with autism and formulate a treatment program for them.
Pros and Cons of Genetic Research on Humans
Current issues in genetic research began far before the Human Genome Project. The sequencing of the human genome has brought about moral, ethical and legal questions. Screening tests now allow parents to find out whether their unborn child will have certain diseases or disorders. Screening tests also are available for women to see if they are more likely than the general population to have breast cancer.
Why is genetic research important? Proponents of genetic research argue that cures for diseases can best be made by determining the difference in gene structure of those affected and those who are not. People can be made aware of potential problems and can proceed as informed individuals. They can inform siblings and family members and encourage additional testing. They have the choice to abort a pregnancy.
Opponents find that if they are feeling healthy with no symptoms, there is no reason to change their life because there is a chance of getting cancer. Pre-natal testing is not a choice since abortion is not an option.
Other reasons include the following:
- Confidentiality is never a guarantee.
- Drugs, like phen-fen have side effects and can cause death.
- Animal testing is inhumane.
The Future of Genetic Research
Genetic research will not go away. But it must be used with caution. Moral, ethical and legal questions will always exist. Hopefully, the two sides will always work together to keep safety the top priority. But rationality and reason must also prevail.
Resources
American College of Neuropsychopharmacology. (2007). First-ever genetic animal model of autism. Retrieved August 28, 2008, from the ScienceDaily Web site: http://www.sciencedaily.com/releases/2007/12/071208092448.htm.
Leach, B. (2007). The road to genetic cures. Retrieved August 28, 2008, from the ScienceLine Web site: http://scienceline.org/2007/02/01/biology-hapmaps-leach/.
Onion, A. (2006). Can geneticists cure obesity? Retrieved August 28, 2008, from the abc News Web site: http://abcnews.go.com/Technology/Health/story?id=1477757.
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