The Disease Lurking In Your Genes

Background:
The concept of DNA testing has been around since the discovery of DNA's composition, but has only been exercised recently in the 21st century. DNA testing in its simplest form is comparing sets of DNA in order to identify their differences and analyze how they are expressed in organisms. DNA testing is relevant to every day life because it is used in paternity testing, forensics, species comparison, migration studies, and, in our case, genetic disease testing. The process of DNA testing involves extraction of DNA, through bodily secretions, skin cells, blood, fingerprints, or hair etc. After DNA is broken out of its cell, the DNA is copied multiple times through processes like PCR (polymerase chain reaction). Gel electrophoresis is the most common process for DNA to be compared through. If the DNA is positive for whatever is being tested, it will align correctly with the bands of the positive control. For this lab, we will use these examples in our procedure.
Purpose:
The purpose of this lab is to fully understand the process of DNA testing. Whether our fields of study will include genetic testing, or if we choose to be tested for genetic diseases in the future, it is important to be aware and knowledgeable.
Procedure:
Day 1: After rinsing our mouths with saline solution to remove foreign particles, possibly containing DNA, we swab the inside of our cheeks to take our epithelial cells that contain DNA. We gain access to the DNA inside by breaking the cell and nuclear membranes with a hot water bath at 95 degrees centigrade. Doing so, leaves the DNA exposed to DNAse which will destroy it, unless we add the Instagene Matrix Beads, which will kill the DNAse.
Day 2: Our next step is PCR, so that we can make multiple copies for research. This involves the following - DNA template (original DNA), deoxynucleotides (raw material), DNA polymerase (enzyme to put them together), Magnesium Ions (catalyst to create the chain), oligonucleotide primers (specify the specific place to begin replicating), and a salt buffer (creates the perfect environment for PCR).
Day 3: The last step is gel electrophoresis. To review, we take the replicated DNA sequences and loading dye and pipette the mixture into the agarose gel. Add the control results for comparison. Now targeting this specific gene, not an actual disease gene because that would have ethical dilemmas, can yield 3 results. Either the sample can be homozygous dominant or homozygous recessive (long strand/long strand or short/short), meaning they are the same, or the third option, heterozygous (long/short).
Results: With the overall class, there were three times as many diseased individuals who tested homozygous recessive. At our lab table, Lizzie was the only one who had definitive results (heterozygous), because the other three of us must have punctured holes through the bottom of the gel, causing it to leak and not give us definitive bands. If we were to get results, we would simply compare the bands of the controls and see with which set our DNA would match.
Discussion: As previously stated, our largest source of error was the gel puncturing. This was extremely disheartening because we are left hanging with the results, because we no longer have our DNA samples. If we had failed somewhere else, we could have done one of the following: insufficient amount of DNA from the cheek cells, using the centrifuge instead of the vortex, or gathering matrix that would have killed the DNA in the PCR machine. After having these results, this will drive us to be more careful next time.