DNA testing is becoming more popular — but how does it really work?

DNA testing kits have developed tremendously in recent times, moving out of the lab and onto the real world. After all, who wouldn’t want to trace their genetic heritage? Most of the time, it only takes a few weeks (and a reasonable sum) to find out where your lineage came from. But how does it work, and how accurate is it really?

Image credits: Micah Baldwin.

Some companies don’t follow strict scientific procedures and essentially, they provide nothing more than doctored tools whose results aim to appease armchair genealogists. However, this isn’t always the case — increasingly often, DNA testing is handled qualified specialists, held to high scientific standards. 

How DNA Testing Kits Work

DNA testing companies provide different types of kits depending on the technologies used to extract your DNA information. The kits are meant to take samples of your skin cells or anything else that can be used to read your DNA.

Most home test kits come with a mouth swab for you to scrap on the inside of your cheeks to get a sample of your saliva and cells. The kits also include information on how to collect your sample, which is very easy to follow. Ideally, DNA testing services would provide three kinds of tests:


  • Autosomal DNA testing


This test evaluates your chromosomes, the thread-like structures that carry your DNA. The goal of the test is to trace your ancestry on both your mother’s and father’s side for up to six generations back. The test also looks into the history of your X chromosome that determines whether you are male or female (females have XX and males have X and Y chromosomes).

If you would also want to track your ethnic heritage, this is the test to take. But as already mentioned, you should go for good DNA testing kits, which can ensure that the results are accurate. The whole procedure is fairly simple: you order the tests online, receive the sampling kit, return your samples, and receive the results in a few weeks. Typically, these tests cost between $40 and $70. 


  • Y-DNA


This is the kind of test you do for paternity tests. The ‘Y’ in Y-DNA refers to the Y chromosomes males inherit from their fathers. The test is important for people who want to discover who their fathers are or prove paternity where it is disputed.

While you can’t use Y-DNA to test your relationship with your female relatives, you can use it on the paternal line of your mother’s side. You could take a test with mother’s father and find your genealogy on that side.


  • mtDNA


This test is relevant to people who would want to test their lineage on their mother’s side. The ‘mt’ in mtDNA refers to mitochondria, a type of small organs found inside cells — you might also know it as the powerhouse of the cell (sic). They are passed down from a mother to her offspring, irrespective of the baby’s gender.

Like Y-DNA, mtDNA only proves that you are related to the people whose DNA matches with yours but doesn’t offer exact details. You could be a match with your friends, but your relationship is through distant relatives. To get more accurate results, it’s recommended that you take the full mitochondrial sequence test.

The DNA Matching Process

After you send your sample back to the testing companies, it’s separated from the others and prepared for DNA analysis. In the labs, DNA testing specialists extract your DNA from the samples given. With your DNA, the experts can track the similarities between your DNA and that of other people.

Cheap DNA testing services tend to analyze your samples for broad matches such that you can’t get results for close relatives. They show you the people you are related with but can’t identify your relationship to them. The best practices can ensure k99.9% accuracy by using a variety of DNA testing methods.

DNA Testing Limitations

DNA testing services don’t say everything about you. If a company claims it can help predict what sports your children will be good at, chances are they can’t. Also, the services vary wildly in accuracy depending on the tools used. Most of the services also deliver your results in percentages. If you are of mixed heritage, your results could be 30% Irish, 25% German and so on.

While they can tell you how much percentage of you is German, the tests can’t tell you where your parents exactly lived. However, you could find out if you are related to a stranger who shares the same maiden name as you do. If you suspect you are related one of your neighbors, these tests can help clear the doubt.

Unique Benefits


  • Reveals your Distant History


While it’s often a point of debate, all humans trace their mitochondrial DNA to one woman who lived more than 150,000 years ago. Nicknamed Mitochondrial Eve, she wasn’t the only woman at the time but she’s the only one whose mitochondrial data can be traced in almost everyone.

With such an extended long lineage, a good DNA testing service can tell a lot about you. Some companies go the extent of showing your relation with Neanderthals, the species evolutions believes preceded us.


  • Discovering Old Relatives


Finding out about your relatives is the main reason for using a DNA testing service. But DNA testing companies go beyond proving your relationship to your parents. Some people have found out about siblings they never thought they had through these services. Others have uncovered dreaded family secrets.


  • Health Information


DNA testing can help reveal your risk of acquiring Alzheimer’s disease or some specific types of cancer. Usually, your doctor’s word is a better piece of advice than what the tests reveal but they still offer a hint of the risk. If a test told you have a 0.1% chance of acquiring breast cancer, that doesn’t automatically mean you have the disease. But if your suspect something, having your doctor check you out can provide a more meaningful diagnosis.

DNA testing services have been around for quite a while. So far, millions of people have used the tests to complete paternity tests or trace their genetic lineage. Not every testing service has been helpful but a lot of the best-rated providers offer accurate results. Considering the technologies used by these services keep on improving, expect DNA testing services to get more popular over the years.

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