DNA Applications: Paternity Testing—Part I

DNA may be small and it may seem complicated but the mystery behind deoxyribonucleic acid is unfolding quickly (even as you read this article most likely). An increased understanding of DNA also continues to generate ideas for real-life applications, many of which are fascinating forms of DNA testing.





How can something so small and composed of seemingly obscure as deoxyribonucleic acid play a part in our lives? One answer is the paternity test.





The Paternity Test: One Application for DNA



A paternity test is accomplished by taking a sampling of a child's DNA and a parent's DNA to exclude or include the possibility of parentage. Testing the DNA of a confirmed parent and a potential parent can help lab scientists determine paternity more quickly but the DNA of two parents is not required. Lab scientists can often prove paternity by exclusion (100% accuracy) or by inclusion (99.9% accuracy).





A paternity test may seem complicated but now that it's down to a science it's not quite the mystery that it seems to have been in the past. I found a brief online explanation¹ which led me to additional questions, additional answers and the rest of this article!





1) The Sampling



First of all, there must be a sampling of DNA taken from a living specimen like you or me. However you can't just reach in and grab a chunk of DNA like you would dig into a cracker barrel. Nope-it's a bit more complicated. The first step of DNA extraction is to take a sample of blood or saliva. (You can easily get a sample of saliva by swabbing the inside of your cheek). This "swab sample" will provide a lab professional with a DNA sample that is still mixed with other molecules and chemical make-ups that you wouldn't need for the paternity test. So, you have to separate the DNA from those other substances. It's like separating the crackers from several other samples that are in the same barrel.





2) The Extraction



Okay. So how do the lab scientists extract DNA from the rest of the substances floating around? This is where the fun begins and you don't even have to be a lab professional to try your own extraction process. Keep in mind however that the paternity test extraction processes may be somewhat different than the process experiment that I am about to introduce to you but many of the principles are still the same.





Some online content² sponsored by the University of Utah shows you how you can extract the DNA from dried peas. The great thing is that you can try this from home. You can take a look at the content for more info but I will show you a quick paraphrased process that can be followed as well:





1) Open the Cell



The online content says you can do this with some water and a blender!


Simply buy a bag of dried peas and blend them with water.





2) Open the Cell's Nucleus



The online content suggests that you use detergent (of the liquid variety)


Open the cell's nucleus. Simply mix the detergent with the pea mixture.





3) Separate the DNA from its Protective and Architectural Proteins



The online content suggests that you use a tenderizer of meats or the


juice from a pineapple to separate the proteins from the DNA sample.





4) Separate the Floating Fats and Proteins from the Floating DNA


The online content suggests doing this by adding alcohol to the pea liquid


Do not mix; the alcohol should create a top layer of liquid over the pea


liquid.





5) Take a Look at Your DNA sample



Since the DNA will choose "to dwell" in the alcohol and the fats and


proteins will stay in the water, the DNA should finally be visible at this


point.





Of course, with human cells, the process might not be so simple, but I think the example mentioned above provides a good visualization of a process that is probably very similar.





To learn more about the next steps in analyzing DNA and to learn more about how DNA might be used in a paternity test, please read part II of "DNA Applications and the Paternity Test." (To locate the article simply "Google" the article title along with my (the author's) name).





¹ http://www.paternity.com/faqs.htm#6


² http://learn.genetics.utah.edu/units/activities/extraction/

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Marci Crane is a web content specialist for Innuity. If you would like to learn more about DNA and DNA testing, please feel free to learn more about Relative Genetics.