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For the first 17 years of my life, I identified myself as half Chinese, a quarter Italian, and a bunch of other things.  Then one day, my dad came home and told us, by the way, we’re part Korean.

I was in shock.  Granted, the amount of Korean I allegedly have in me (1.1%) is so small, it barely counts.  However, I have always considered my ethnic background an essential part of what makes me me.  For so many years, people have kept track of their backgrounds based on what their ancestors passed down or any records they could find, but today there are new ways to test genetics.

One of these ways is a spit test, which is how I found out that I’m (part!) Korean.  My uncle had a DNA test done for medical reasons and was sent additional information about his race in the process. To do this, he simply had to spit in a bag, mail it out, and send along $100.  While I think this is really cool, I also wonder how it works and whether it’s reliable. After all, he literally just spit in a bag.

It started in 1985, when English scientist, Dr. Alec Jeffreys, noticed that certain sequences of DNA repeated itself, and the number of repetitions varied among people, according to John Butler’s book, Forensic DNA Typing.  He used these observations to start performing human identity tests.  Since then, the use of DNA testing has grown rapidly in many different fields.

According to the New South Wales Government Fact Sheet, DNA tests can be done using body tissues like blood, skin, saliva, and hair follicles.  It states, “DNA to be tested can be extracted from the cells of a variety of body fluids or tissues.”  After the samples are taken, the DNA is cut into smaller pieces, called sites, and then they are placed in a gel matrix.  The gel is charged so that there is a positive and negative end.  Since DNA is negatively charged, it will move towards the positive end, but the speed at which it moves depends on the size of the DNA piece, so larger DNA pieces will go a shorter distance.  After the pieces have separated, a probe is placed on top to compare the patterns of the DNA.

Often times, the scientists will use a naturally occurring enzyme to reproduce more of the DNA since it is easier to analyze the genetic code when there are more samples, according to BBC Science.  Much of the decoding is based on comparisons.  BBC Science likens the process to comparing fingerprints.  Since 99.9% of people’s DNA is the same, the DNA test is looking at the 0.1% that makes each person different.

There are many different uses for DNA testing, including forensics, confirming parentage, and looking for genetic diseases.  In my uncle’s case, he was looking for evidence of genetic diseases, but he also got back information about his heritage.  According to the University College of London, the Y-Chromosome would have been tested for his male ancestry.  Based on what appeared in the results, his DNA was matched with the region that shows men with similar DNA patterns.  The testing center might have also done a mitochondrial test for his female ancestry.  UCL states that the results may “be accompanied by a story and a ‘migration map’” to help pinpoint where his ancestors are from.

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Blogger Emma Jolly decided to do three different DNA tests through three different companies.  She found that each one sent back similar results when it came to her main ethnicity, but, as they tried to work farther back in her family tree, there were discrepancies among the different test results.  Since testing and categorizing is based on comparisons, the more DNA entered into the databases, the more accurate the results will be.

There are so many different uses for DNA testing, and the accuracy of the tests depend on what each is looking for.  When it comes to confirming parentage, it is more accurate because there are two definite DNA samples to compare.  If genetic screening or testing is being done, the tests can spot whether someone is carrying a certain genetic trait or has the pattern that is common among diseases.  However, it cannot always confirm that that trait or disease will appear and affect that person.  Finally, when it comes to determining heritage, the DNA tests can spot the more evident ethnicities, but, since it is based on comparisons, it is not entirely accurate as it goes farther back.

Since I am interested in history and heritage, I look forward to when the tests can more confidently identify ancestry.  For now, it appears that, to be more positive of the results, people must take more than one DNA test and compare the results.  However, unless there are  documents proving that the ancestry the DNA tests recover, there is no way to confirm that what the test is saying is right when it comes to heritage.  As time goes on, the science of decoding DNA will become more and more accurate, and with the progress will come many enlightening facts as well as many new ethical questions.