To the end consumer, DNA testing is reasonably straightforward; follow the instructions on the kit and let the service tell you about your genetics. However, advanced technologies power affordable at-home DNA testing, something that would have been impossible only a few decades ago. This guide will run through DNA testing 101:
The concept of genetics started over 150 years ago, with experiments on pea plants by Gregor Mendel. The field has evolved into a refined science with humongous strides, especially over the last two decades. The first human DNA test was completed in June 2000 at the cost of an estimated $150 million.
By the end of 2006, DNA testing had dropped to about $14 million but remained mostly inaccessible to even the well-connected. Today, a full sequence might cost you around $1000, but consumer kits - convenient at-home DNA testing - can be had for only $70 to $200.
Every living human cell contains a special compartment known as the nucleus - often called the ‘brain of the cell’ - that contains and protects our DNA. From here, instructions are transcribed from your DNA blueprint that dictate the actions, development, and growth of your cells. The entire sequence of your DNA is unique - barring identical twins - but all the discrete parts, or genes, were inherited in roughly equal measure from your parents - 50% each.
This inheritance is the basis of genetics and the reason why some diseases or traits are found throughout family lines. It also forms the foundation of DNA testing for ancestry - some ‘markers’ found within your DNA can be traced backward, through your father- and mother-lines, for thousands of years. These lineages are kept separate:
This situation means that anyone can test their motherlines through mitochondrial DNA testing, but only genetic males can have their fatherlines analyzed. However, markers in the other 44 chromosomes - or autosomal DNA - can be used to construct ancestry estimates for at least five generations. With this in mind, make sure you understand what you want to find when you test your DNA for ancestry:
|Goal||Trace Father’s Line||Trace Mother’s Line||Find Family|
|Test||Y-DNA test||mtDNA Test||Autosomal|
DNA testing is suitable for anyone who wants a better view of their health and how their DNA affects it, as well as examining their ancestry and the construction of family trees. However, make sure you’re familiar with the pros and cons of genetic testing and what genetic testing may reveal. One can discover - through DNA testing - health conditions they carry or are predisposed to, learn or confirm paternity, suggestions on how to best build muscle, and even sleep trends.
While the industry is still in its infancy - along with the research that underpins it - some information is better than none when it comes to genetic testing. Cheap, consumer DNA testing gives you a wealth of medical knowledge and a blueprint of you, something that will only become more valuable as time goes on.
If you are prone to hypochondria or anxiety, taking a DNA test might not be for you, or may be best guided by a medical professional. This is a process that is supposed to be fun, informative, and enjoyable and not promote excess worry. The best way to ensure a positive experience is to educate yourself thoroughly before you begin.
Every at-home DNA test is different in their own ways, but each follows the same general premise:
How to Take an At-Home DNA test
The first step is ordering the testing kit from whatever site you’ve decided to use. Use our reviews to explore the strengths and weaknesses of each test.
Next, you will receive a saliva collection kit (either a spit tube or a cheek swab) and instructions for providing your DNA sample (registering your kit, etc.). Saliva contains skin cells which, like all human cells, contain DNA suitable for analysis.
Roughly 99.5% of human DNA is identical from person to person. However, there are little differences - known as variations or mutations - that make each individual unique. The lab extracts DNA from the cells contained in your sample, then processes the DNA to scan hundreds of thousands of variations throughout your genome.
Finally, your DNA data is examined, and personalized genetic test results are created according to well-established medical and scientific research. Further, your DNA can be compared to other people in the company’s database to see if you share enough matching variations to suggest a blood relationship.
This is a complicated question without an easy answer; we devoted an article entirely to the topic. In short, it’s easier to answer this if Ancestry and Health aspects of DNA testing are separated, as they rely on different foundations to power their accuracy.
DNA testing is very good at finding closely related family members, exemplified by its frequent use in forensic science and law enforcement. It’s fully expected that you will find any 1st or 2nd cousins - and other relatives that might be equally removed - that have taken the same test. Unfortunately, they are not nearly as accurate when determining your ancestry and ethnicity, much less the specific locations where your ancestors lived. In this regard, the services are merely comparing your DNA to those with confirmed and documented ancestry. The general regions will most likely be correct, but the specific countries might not be exactly perfect.
For 23andMe to include genetic health reports, it had to undergo a lengthy FDA approval process to demonstrate that their results could be reproduced 99% of the time in clinical labs. However, to avoid the sticky issue of ethical concerns and informed consent, most of the results are of a generally lower impact than what could be conveyed.
While the accuracy of the reports isn’t an issue per se, many results are not immediately actionable or even understandable. 23andMe tries to head this off at the pass by making you complete tutorials before it allows you to see health-related risks and predispositions, but the problem can still occur.
|Company||Database Size||Sales (est)|
|Ancestry.com||15 million||14 million units sold|
|23andMe||10 million||5 million|
|Family Tree DNA||1 million||Unknown|
|MyHeritage DNA||2.5 million||Unknown|
|National Geographic DNA||Unknown||Unknown|