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MCAT Content / Recombinant Dna And Biotechnology / Practical Applications Of Dna Technology Medical Applications Human Gene Therapy Pharmaceuticals Forensic Evidence Environmental Cleanup Agriculture

Practical applications of DNA technology: medical applications, human gene therapy, pharmaceuticals, forensic evidence, environmental cleanup, agriculture

Topic: Recombinant Dna And Biotechnology

Biotechnology is a rapidly developing field that has evolved techniques for improving fields such as agriculture and medicine to help develop better lives.

Medical Applications

Biotechnology is rapidly growing and is developing techniques for preventing, diagnosing, and treating diseases. Polymerase chain reaction (PCR), gene sequencing, fluorescence in situ hybridization (FISH), microarrays, cell culture, gene silencing using interference RNA, and genome editing have contributed towards medical science. These have helped sequence the human genome, the use of stem cells for regenerative medicine, tissue engineering, the development of antibiotics and vaccines, and the generation of monoclonal antibodies for therapy.

Human Gene Therapy

Gene therapy uses modified viruses to deliver genes to somatic human cells to correct or supplement a defective gene. The targeted gene will incorporate into the genome of the cell correcting the defect. If gene therapy is successful it can be used to treat sickle cell anemia and Parkinson’s disease.


Recombinant DNA is useful to pharmaceutical companies to help with drug production. An expression plasmid is created and transformed into bacteria. The bacteria is then either lysed if the drug of interest is produced intracellularly or the growth media is collected and the drug of interest is purified if the drug is secreted from the cell. DNA segments can be cut from one source to another in order to develop vaccines. The gene for a surface protein of a harmful pathogen can be cloned into a harmless virus and administered through a vaccine. The body will recognize this as a foreign body and stimulate a response, providing immunity against this type of virus with eliciting a harmful pathogen.

Forensic Evidence

Restriction fragment length polymorphisms (RFLPs) are differences among individuals in the lengths of DNA fragments cut by enzymes. RFLPs analyze the length of strands of DNA that include repeating base pairs known as variable number tandem repeats. These differences were examined in DNA samples collected from a crime scene among suspects of a forensic case to identify the perpetrator.

Short tandem repeat (STR) analysis is another method used in forensic cases. It can start with a much smaller sample of DNA compared to RFLPs. Investigators amplify this sample through PCR. Once the DNA is amplified, STR analysis examines how many times base pairs repeat in specific loci on a DNA strand. This method is more widely used today to identify DNA samples at a forensic crime scene because it takes less time.

Environmental Cleanup

Genetically modified bacteria have been developed to help with sewage problems by degrading harmful compounds and speeding up the degradation process. Bacteria has also been modified to extract heavy metals from the environment, which can be beneficial to the mining process and the extraction of toxic mining waste. Genetically modified pigs produce an enzyme in their saliva that has the ability to breakdown indigestible phosphorus. These modified pigs may help decrease water pollution since the phosphorus can be broken down and prevent algae growth.


DNA technology has impacted agriculture in a number of ways. One way is by optimizing crop yield by transferring certain genes. As an example, certain plants express a transgenic enzyme that is harmful to pests, decreasing the need of pesticides. Another example is certain plants have enzymes resistant to diseases and herbicides increasing crop yield. The ability of plants to fix their own nitrogen allows farmers to save money on fertilizer. If scientists can isolate this gene from legumes, this have a beneficial impact on the environment. A certain modification in specific foods has increased nutritional value and shelf life. Golden rice has been developed to contain beta-carotene to help combat vitamin A deficiency and tomatoes have been developed to be firm from the start of harvest allowing them to be fresh when they arrive at the grocer.


Practice Questions

Khan Academy

MCAT Official Prep (AAMC)

  • Biology Question Pack, Vol. 1 Passage 5 Question 31
  • Practice Exam 4 B/B Section Passage 3 Question 18


Key Points

• Recombinant DNA and biotechnology have been applied to various fields such as medicine, agriculture, environment, forensics, gene therapy, and pharmaceuticals

• Certain isolation of genes in plants has improved agricultural science

• Forensic investigators have been able to identify suspects by using RFLP and STR analysis

• Gene therapy has the ability to cure diseases such as cancer and immune disorders

• Pharmaceutical companies have developed better drugs through the use of recombinant DNA and biotechnology

• The environment has been cleaned up due to genetically modified animals and bacteria

Key Terms

Expression plasmid: a plasmid or virus designed for gene expression in cells. The vector is used to introduce a specific gene into a target cell

Recombinant DNA: DNA that has been formed artificially by combining constituents from different organisms

FISH: fluorescence in situ hybridization that uses fluorescent probes that bind to only those parts of a nucleic acid sequence with a high degree of sequence complementarity

PCR: Polymerase chain reaction is a method used copies of a specific DNA sample rapidly

Microarray: a laboratory tool used to detect the expression of thousands of genes at the same time

Stem cells: special human cells that have the ability to develop into many different cell types

Gene therapy: an experimental technique that uses genes to treat or prevent disease

Restriction fragment length polymorphism: is a type of polymorphism that results from variation in the DNA sequence recognized by restriction enzymes

Genetically modified: organisms in which the genetic material (DNA) has been altered

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