)
PCR Protocol
How Polymerase Chain Reaction Works
Utilizing DNA polymerase enzyme, PCR synthesizes complementary strands from a targeted segment of DNA. Test tubes within the PCR machine work need ample mixtures of the four DNA bases (Adenine, Thymine, Guanine, and Cytosine) to recreate the desired DNA sequence. The test tubes also need primers to kick-start the DNA replication process. Due to this, people who want to amplify DNA need to know the region of DNA they want to copy.
How to Amplify a Patient’s DNA Sample
1. Extract DNA from the patient you are running tests on
2. Place your extracted DNA in a PCR tube (suited for rapid heating and cooling)
3. Remember if you’re using a pipeter, you need to replace the tips before pipetting new chemicals (to avoid cross-contamination)
4. Add primer 1 to the PCR tube – specialized to cut the DNA segment at the front of the desired part
5. Add primer 2 to the PCR tube– specialized to cut the DNA segment at the back of the desired part
6. Add nucleotides (A, T, C, and G) to the PCR tube- to aid in the synthesis of replicated DNA
7. Finally, add DNA polymerase to the PCR tube- the enzyme responsible for DNA replication (or here amplification).
8. Place the PCR tube into a PCR machine or DNA Thermal Cycler – this expedites the DNA replication process.
9. The settings for your PCR machine should be as follows:
Cycle 1 a. heat to 95°C to denature the double helix of DNA then b. cool to 55°C to activate primers then c. heat up to 72°C to activate DNA polymerase
10. Cycles repeat to amplify DNA
DNA Measurement Protocol
Research and Development
Background on Disease Markers
A very large disease that is wide spread all around the world is Alzheimer’s. Nearly one in every 85 people around the world has this disease. On average, one’s life will end seven years after the diagnosis. Fewer than three percent of patients live longer than fourteen years after the determination of the presence of Alzheimer’s. Of the type of Alzheimer’s that is autosomal, the DNA produces a protein that is different than the expected one. This misfolded protein causes the disease. The DNA sequence that codes for the specific amino acids that form these mutated proteins are called SNPs. An Alzheimer’s related SNP is called rs429358. It exists on the 19th chromosome of the human genome. More information about this SNP can be found by looking up the reference number, rs429358, on OMIM. The normal sequence appears TGC while the mutated Alzheimer’s sequence will show CGC. The respective amino acid produced changes from Cysteine to Arginine. This change in amino acid, causes the proteins to fold differently.
Primer Design
The reverse primer for this gene would be: GGCGGCCGCACACGTCCTCCCA. The critical sequence begins at 45,411,950 on the 19th chromosome.
Now looking 200 base pairs to the left, a forward primer can be created. In this case it would go as follows: CATCCCAGCCCTTCTCCCGC.
Illustration
An Illustration of the Amplification of DNA
This image displays the location of the DNA in the nucleus and the exponential rate of amplification, 2 raised to the n.
|