Course: SAT 170 Introductory Biotechnology

Unit 11 Reading and Multimedia Assignment

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“Biotechnology in Agriculture," by Boundless, CC BY SA 3.0

https://www.boundless.com/biology/biotechnology/biotechnology-and-everyday-life/introduction-to-medical-uses-for-dna-technology/
Reading Assignment: Introduction to medical uses for DNA technology
New technologies, such as PCR, have been instrumental in improving the diagnosis of diseases.

Many of the new technologies described in this chapter have been instrumental in improving the diagnosis of diseases. The polymerase chain reaction (PCR), for instance, has been applied to a large number of medical procedures. The first application of PCR was for genetic testing, in which a sample of DNA is analyzed for the presence of genetic disease mutations. The genes that cause sickle cell disease, Huntington's disease, cystic fibrosis, hemophilia and other devastating diseases have all been identified. Prospective parents can be tested for being genetic carriers, or their children might be tested for actually being afflicted with a disease. DNA samples for prenatal testing can be obtained by amniocentesis, chorionic villus sampling, or even by the analysis of rare fetal cells circulating in the mother's bloodstream. PCR analysis is also essential to preimplantation genetic diagnosis, where individual cells of a developing embryo are tested for mutations.

PCR can also be used as part of a sensitive test for tissue typing, vital to organ transplantation. As of 2008, there is even a proposal to replace the traditional antibody-based tests for blood type with PCR-based tests. In addition, many forms of cancer involve alterations to oncogenes. By using PCR-based tests to study these mutations, therapy regimens can sometimes be individually customized to a patient.

The characterization and detection of infectious disease organisms have also been revolutionized by PCR. The Human Immunodeficiency Virus (or HIV), responsible for AIDS, is a difficult target to find and eradicate. The earliest tests for infection relied on the presence of antibodies to the virus circulating in the bloodstream. However, there are many issues with this model: antibodies don't appear until many weeks after infection, maternal antibodies mask the infection of a newborn, and therapeutic agents to fight the infection don't affect the antibodies. PCR tests have been developed that can detect as little as one viral genome among the DNA of over 50,000 host cells. Now, infections can be detected earlier, donated blood can be screened directly for the virus, newborns can be immediately tested for infection, and the effects of antiviral treatments can be quantified.

Some disease organisms, such as that for tuberculosis, are difficult to sample from patients and slow to grow in the laboratory. PCR-based tests have allowed detection of small numbers of diseased organisms (both living and dead), in convenient samples. Detailed genetic analysis can also be used to detect antibiotic resistance, allowing immediate and effective therapy. The effects of therapy can also be immediately evaluated.

In the future, personalized medicine may become more common. Inexpensive, time-efficient full genome sequencing will be a major accomplishment not only for the field of genomics, but for the entire human civilization. For the first time, individuals will be able to have their entire genome sequenced. Utilizing this information, it is speculated that health care professionals like physicians and genetic counselors will eventually be able to use genomic information to predict what diseases a person may get in the future and attempt to either minimize the impact of that disease or avoid it altogether through the implementation of personalized, preventive medicine. Full genome sequencing will allow health care professionals to analyze the entire human genome of an individual and therefore detect all disease-related genetic variants, regardless of prevalence or frequency. This will enable the rapidly emerging medical fields of Predictive Medicine and Personalized Medicine and will mark a significant leap forward for the clinical genetic revolution.