How Does DNA Testing Work, Why Get Tested?

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Microscope: DNA Testing 101: How Does DNA Testing WorkWhen most of us think of DNA, we picture crime scenes from TV shows like “CSI” or a homicide trial in which DNA evidence convicts a killer. Forensic testing aside, there are also many practical applications for DNA testing. And more people are getting their DNA tested now than ever before, thanks to scientific advances and the growing popularity of at-home DNA testing kits. What are some of the reasons for DNA testing? And just how does DNA testing work? We’ll help you unravel the mystery of DNA testing.

Why Get My DNA Tested?

DNA stands for “deoxyribonucleic acid,” and everyone’s DNA is unique to the individual. Most DNA tests involve the collection of saliva from the inside of your cheek using a simple cotton swab. The swab then goes to the lab for analysis. Not every DNA test, however, is the same, and not every test’s design finds the same information from your DNA. It’s important to do your research about the type of test and the lab processing your DNA to make sure they’re testing your DNA for the specific information you’re looking for. Here are the major types of DNA testing:

  • DNA Ancestry Test: DNA testing for ancestry is growing in popularity as more and more people want to know about their family history. A DNA ethnicity test can help you discover your ethnic origins from around the world. And DNA testing for genealogy can also help you identify your ancestors and living cousins you never knew you had. Read our DNA Ancestry Test Comparison
  • DNA Paternity Test: One of the more common types of DNA tests, a paternity test determines the biological link between a father and child. There’s even a non-invasive prenatal paternity test available now. Read our Paternity Test Comparison.
  • Genetic Testing for Carrier Status: Want to start a family, but you’re worried you may pass on an unwanted risk to your child? Some DNA tests can tell you if you’re a carrier for certain inherited conditions, such as cystic fibrosis, sickle cell anemia, hereditary hearing loss. A positive match doesn’t mean your child will inherit the condition; it just lets you know whether you carry the gene.
  • Genetic Testing for Cancer Risk:  Most people don’t need this type of DNA testing. But some people have a higher risk of developing specific types of cancers that tend to run in the family. In these cases, a physician may test your DNA to look for gene mutations that could indicate a higher risk. One of the better-known examples is testing for mutations in the BRCA1 and BRCA2 genes (breast cancer genes) in women whose mother and sister have had breast cancer.

What Can a DNA Ancestry Test Tell Me?

Celebrities and other famous figures have joined the DNA ancestry testing bandwagon. Check out this video that reveals the ethnicity results for Mario Lopez and his wife. There’s always a surprise or two in store!

Where Can I Get a DNA Test?

Family Tree DNA logo
Ancestry DNA logo
23andMe logo

If you’re wondering how to get a DNA test, it depends on your purpose for DNA testing. Most ancestry tests are available as home DNA test kits, which you can order online and have shipped to your home (see our top 3 picks on the right). All you do is swab your cheek, place the sample in a container they provide and mail it back to the lab in pre-paid packaging. You’ll receive your results anywhere from 4 to 10 weeks, depending on the company.

You also can order an at-home paternity test, but be aware that these won’t cut it in court. In this case, you must get a legal DNA paternity test at a certified lab.

In the case of genetic testing for a possible cancer risk, you’ll want to consult with your physician first. A lab tech usually administers this type of DNA test at your doctor’s office or hospital.

How Does At Home DNA Testing Work?

You know what types of tests exist and figured out which one you want to take. Now what happens? We’ll share from our own first-hand experience how it works from start to finish. We should note that we were provided with a test kit from LivingDNA at no cost to us. Our research is unbiased, read about our review process here. Next we’ll walk through the process step by step for you so you know what to anticipate when you do your own.

Step 1: Order & Activate Your Kit

Depending on what you are looking to accomplish in the types of tests above, you’ll order your kit online from anywhere in the world. It takes about a week to receive. The package should arrive sealed so you can assure no one else has tampered with it. You might be anxious to get started in the sampling process, but first you’ll need to activate your kit online using a unique code provided to you. This connects your name and contact info to your sample so you can track progress as it’s tested and view results. You’ll most likely sign a consent form and agree to their terms and conditions before getting started (for legal purposes).

Step 2: Provide DNA Sample

Living DNA Sample tubeNow for the fun part – providing your DNA sample! Family Tree DNA (FTDNA), Living DNA and MyHeritage DNA offer cheek swab tests. AncestryDNA and 23andMe tests require you to spit in a vial. Either way, they recommend not eating, drinking, smoking or chewing gum at least one hour before to ensure a good sample. Also wash your hands before opening the test tubes to ensure a good, clean sample.

Step 3: Seal & Ship

Once your samples are complete and ready to go, seal the samples in the specimen bag, put them in the pre-paid mailing envelope, and drop the envelope in your mailbox.

Step 4: Wait For Results

In an age where we can get things instantaneous, you might be anxious to get results. But given the complexity of the process of analyzing your DNA and comparing your results to other samples, expect to wait anywhere from 4-10 weeks (depending on the company). And if you’re curious where they are in the process, you can login to track their progress.

Step 5: View & Share Your Results

To access your results, login to your online portal you created when you activated your kit (they do not mail them to you for privacy reasons). Once logged in you can view and analyze your DNA using percentages, maps and more (depending on which kit you went with).

Easy right? No doctor’s office visits or intimidating scientists. You can take a test and get results back all from the comfort of your home.

How Accurate is DNA Testing?

DNA testing for forensic purposes, paternity and ancestry are 99.9% accurate. The lines are a bit more blurry when it comes to DNA testing for disease risk. The Centers for Disease Control and Prevention and other federal organizations want the public to be aware that many companies are prematurely marketing genetic tests for disease risk with limited scientific backing. Many of these tests may not provide valid or useful results. Why? Researchers have yet to identify a large part of the genetic makeup with most diseases.

The takeaway? Although DNA analysis has come a long way, DNA testing for most medical and health-related purposes is still in its infancy. Always consult your physician about these types of tests.

Infographic: DNA Tests

Here’s an infographic that summarizes DNA tests in a nutshell.

Infographic: DNA Tests

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For which test is best for what purpose, testing FAQ’s, and a video on shocking success stories, check out our DNA Testing 101 article.

What advice do you have for people considering DNA testing?

An international traveler since she was under 10 years old, Sally loves exploring the world’s mysteries first hand. Her favorite destinations? Greece and the British Virgin Islands. She grew up learning to question, explore, and discover new things and ideas — it’s probably why she went into journalism as a career! She loves what the Internet has brought to research and exploration, but she still hits the ground to travel whenever she gets the chance.

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2 Comments on "How Does DNA Testing Work, Why Get Tested?"

Daniella R
Daniella R

I have a general question in regards to DNA testing – I’ve noticed that all these genetic test products have flooded the market in the past decade. What scientific progress has suddenly made all this possible – was it the sequencing of the human genome?


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