Human Genetic Screening

Introduction

The Technical Aspects of Genetic Screening

Genetic screening is now used every day, when an amniocentesis is performed the fetus has just undergone genetic screening. Scientists can detect disease-baring mutations, test for genetic predisposition to diseases, and discover some physical characteristics and behavior traits that lie within your genes, all through genetic screening (White par 2).

Many types of genetic tests are available today. The most common type is newborn screening. Blood samples of newborns are tested for abnormal or missing gene products, some of these tests look for abnormal arrangements of the chemical bases in the gene, while other tests detect inborn errors of metabolism by verifying the absence of a protein that the cell needs to function normally. Prenatal screening is testing during pregnancy to determine whether a baby has a genetic condition or is at risk of one. Chorionic villus sampling and amniocentesis are the most common types of prenatal tests (Facts Sheet par 2). Carrier testing is another form of genetic screening. These tests tell a person if they carry a recessive allele for inherited disorders, also telling them if they are at risk of passing that allele onto their children. Carrier tests are helpful in early detection, diagnosis, prognosis, and treatment of the disorder one may be carrying. A third type of test is predictive gene testing. These tests identify people who are at risk of getting a disease, before any symptoms even appear. Symptomatic testing is done on those with specific medical findings, physical features, or developmental problems. This test helps attain correct diagnosis and a plan of treatment. All of these tests look for abnormalities in whole chromosomes, in short stretches of DNA within or near genes, and in the protein products of genes (Understanding Gene Testing).

Genetic screening is also done in the form of DNA fingerprinting and identity testing. This testing takes advantage of the fact that the DNA of each person, except identical twins, is different (DNA Fingerprinting par 2). There are two methods of DNA fingerprinting. The first is Restriction Fragment Length Polymorphism (RFLP). In this procedure small DNA fragments are removed from the molecule by enzymes. Radioactive probes bind to the DNA areas that are used to establish identity, and X-ray film detects the pattern. The film is then developed and the fingerprint is compared to other samples. RFLP may take several weeks to complete and relies on large samples that must be uncontaminated by any other DNA fragments. The second, less time-consuming test is Polymerase Chain Reaction (PCR). This procedure uses repeated cycles to reproduce a target area of DNA until enough copies are available for analysis.

Genetic screening is also used in paternity testing. In this procedure, samples from the mother, child and suspected father are tested. Since every child inherits half of its genes from it's mother and the other half from its father, by examining the mother's and child's genetic markers, it can be determined what genetic markers must come from the father. If the suspected father does not show two or more markers necessary for paternity, he is excluded. If he shows all the markers, mathematical analysis is done to determine the likelihood of him being the father (Analytical Genetic Testing par 1-4).

The Pros and Cons of Genetic Screening

Although there are many pros to genetic screening, there are just as many, if not more, cons to screening. Financial aspects are one con of screening. Even though early detection is usually cheaper by means of treatment than later detection, genetic screening is not a small expense and in most or all cases, insurance companies will not cover the expense. Another issue of screening is the idea of privacy. If you are screened for a genetic disorder and you find that you are at high risk of developing that disorder, whom do you have to tell and whom does your physician have to disclose this information to? Does your family have the right to know? What about the mighty insurance company? If they find out about this disorder they are likely to drop your coverage, and not many insurance companies will be willing to cover you. Your career may also be in jeopardy if your employer catches wind of your likelihood of a disorder. There are also technical limitations to genetic screening. No test is 100% accurate in implicating whether you are at high risk or low risk of the disorder. A mistaken result could lead to many different situations, which wouldn't need to be dealt with if the test was correct in the first place. Another surfacing idea is humans playing God . With genetic screening, parents are able to find out a lot about their unborn child, if they find something they don't like, they have the freedom to abort the child. Is it right that we can pick and choose the traits of our children? An additional con to genetic screening is the psychological effect it may have on a person said to be at high risk for developing a disorder. True, a study did show that most patients were relieved; what about the one's that weren't so relieved to know? In the case of DNA fingerprinting and paternity testing, these test are not 100% accurate and can lead to great financial (in child support cases) and psychological turmoil.

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