You can’t watch a crime drama on TV, or the news (think Anna Nicole Smith) for very long nowadays without hearing about DNA. DNA testing can tell who fathered a child. It can rescue an innocent inmate from prison, or prove the case against a criminal. DNA testing can give you an idea of certain diseases you are more likely to develop than other people. DNA can also link you with your ancestors and show you where they might have come from.
But what exactly is DNA? Deoxyribonucleic Acid is a sort of blueprint for every cell in your body. Your genes are made from DNA. You get half from your mother, and half from your father. The only two people that can have identical DNA are identical twins. In every other case, DNA is a so-called genetic fingerprint. Because it is unique, police and prosecutors look to DNA samples to help catch and convict criminals. In the legal system, DNA samples must be handled carefully.
But people can take their own DNA tests in the privacy of their homes. A blood sample is not necessary. All that is needed is a few cells from the lining of the cheek. A scraping of the lining taken with a swab is enough to do DNA testing. It is most commonly used to determine paternity.
The kit for the test can be ordered online, or bought at a drugstore. The cost for a simple paternity test runs between $100 and $250. You take your own sample, and send it to the lab. If you are trying to establish paternity, you also need a swab of the possible father’s cheek, and of the child’s cheek. Most labs that do this testing say that they can tell you with greater than 99% accuracy if the person sampled is the child’s father, and 100% if he is not.
There are also ways to get the possible father’s DNA surreptitiously. Sometimes labs can run the test from a piece of chewed gum, or a hair. Each lab is different, and less-than-perfect samples cost hundreds of dollars more to test.
What else can you do at home? You can prove other familial relationships if there is some question. You can also have your DNA tested to look into your ancestry. The National Geographic Society is even collecting DNA samples from all over the world to create a sort of genetic world map. You can participate by conducting an at-home DNA test, which costs about $100.
Some other types of home DNA testing are probably best avoided. One company says it can tell you as early as 7 to 8 weeks into a pregnancy what the sex of the unborn baby will be. This is allegedly possible because some of the baby’s blood mixes in with the mother’s blood. You take a sample of the mother’s blood at home. If the lab finds a Y chromosome in any of the sample, the baby will be a boy, because only males have a Y chromosome. If no Y chromosome is found, the baby will be a girl. This whole area of DNA testing is not proven, and there are lawsuits at the current time against companies that reported the unborn child’s sex incorrectly. There are also ethical issues even if this test were to be perfect.
Another category of DNA testing exists, genetic testing for markers of certain medical conditions. Usually, if this kind of test is necessary, your doctor will order it, and it will be done in a lab that is certified to give accurate results. More importantly, your doctor can advise you what the test means. If you have a certain gene, you have an increased probability of developing a certain disease. It doesn’t mean you will get the disease, and a negative test does not mean you won’t.
You can do these tests at home. But you will not have anyone to explain what the results really mean. Still, people do these tests, sometimes for privacy, or in order to prevent health insurance companies from knowing the results and perhaps raising their rates. But to test for the right conditions and actually understand what the results mean, you should see your doctor, or in some cases, a geneticist.
As of today, at-home DNA testing is best used to determine paternity or other familial relationships when there is no legal requirement, or to get information about your ancestry.