How DNA Testing Services Work by Mail
If you want to learn about your origins, find long-lost family members, or see clues about which health and personality traits you may have inherited, you will probably start by spitting on your phone.
If you don’t catch the sale, you will probably pay $ 100 or more for this privilege. Ancestry is taking $ 99 right now. 23andme’s regular price is $ 99 for a service intended only for their ancestors, and $ 199 for a version that includes health and other features. Helix charges $ 80 for sequencing, but you’ll have to link that with an affiliate service to really learn a thing or two. For example, DNAPassport costs $ 29. (Once you’ve submitted one sample to Helix, you can buy other partner services without paying again for sequencing.)
Genetic companies like 23andme, Ancestry, and Helix ask for your saliva because it’s one of the easiest ways to get a DNA sample. There is a fill line, and you’ll have to spit a dozen or more times to get to it. The saliva sample will float the cells in the inner lining of your cheeks, as well as the white blood cells that are naturally present in saliva . The laboratory steps will open up these cells, separate their DNA from everything else in your soup, and read some of the letters.
What data can be obtained from DNA?
Each of our (usually) 46 chromosomes is just a really long DNA molecule made up of four bases – adenine, thymine, guanine, and cytosine – arranged in a specific order that determines the information for our cells. Every little enzyme that helps us burn fuel for calories can be built somewhere in this code from a blueprint. It’s the same with the proteins that make up our muscles, the receptors that our cells use to detect hormones, and even the mechanisms that make more DNA. If our body does this, then it’s somewhere in the code.
There are billions of these chemical letters in our DNA, and each one is still expensive to read. Thus, companies choose one of two labels.
23andme and Ancestry don’t read your DNA sequence directly. Instead, they expose the DNA soup to glass chips called microchips. Each chip has many tiny spots that light up red, green, or yellow when certain patterns in DNA are detected. A quick scan of the chip on a computer gives you a list of DNA regions – about 600,000 in the current version of 23andme – and what letters you have on each. Both of these services have tools on their website to study what your DNA results mean, but you can also just download the file yourself: here are the instructions for Ancestry and for 23andme .
Helix, the lab that has created many new services like the one that correctly guessed my children’s hair color , works a little differently. Instead of selecting specific letters, the Helix laboratory reads millions of nucleotides (code letters) and keeps this information secret. When you buy an affiliate service, such as babyGlimpse, you only allow the affiliate to access the data they need to provide their services. (Helix asks partners to handle data responsibly, but you will still want to read this privacy policy carefully.)
Helix gets more data than 23andme, but in practice, both often use their data in the same way: to identify variants, called SNPs.
Know your SNPs
While we are all unique and special individuals, we all share much of our DNA. More than 99 percent of my DNA and yours will be identical, even if we are not related. And each of us has approximately 98.8 percent of chimpanzee DNA .
Therefore, it is inappropriate for genetic companies to look at our entire DNA. Instead, they focus on small areas where people tend to differ from one another. Maybe I have two A’s, and you have A and G. (We have two almost duplicate copies of our DNA, one from each parent. Maybe A came from your mom and G from your father).
These spots, which are known to differ, are called single nucleotide polymorphisms or SNPs (pronounced “scissors”). Sometimes SNPs are found in an important part of protein building instructions, and as a result, people with different SNPs create different versions of the protein. In other cases, the SNP is an innocent bystander, just a small flag that researchers note is usually present in people with a certain trait. For many SNPs, scientists do not know why this SNP is associated with a particular trait. However, if the trait is interesting, they will try to do more research to figure out the cause.
Even if you’ve used Helix to sequence large chunks of your DNA, many of its partner services still use SNPs rather than all other data to get you results. Some services will use Helix or 23andme data of your choice.
What can be done with genetic data
When you have this data, people like the following:
- See how many of your SNPs you share with people from other parts of the world . This is the basis for many tests that promise to show you where you are. You can even get reports that tell you how much DNA you have from prehistoric peoples such as Neanderthals or Denisovans.
- Look for SNPs that relate to your personality traits. You can find out if you have common SNPs associated with lactose intolerance or caffeine sensitivity. You can also check to see if your genetics are correct in predicting eye color and other traits for which you already know the answer. There are companies that can use your DNA to try and predict your ideal weight loss diet or which wines you might like .
- Find out if you have health-related SNPs. Consumer DNA tests are not the best way to find out, for example, if you have a breast cancer gene, but if you have a raw data file, you might be curious about what it contains. If you think you have discovered something that is seriously affecting your health, talk to your doctor or genetic counselor about it .
- Transfer your raw data to another service. If you have a file from 23andme or Ancestry, you can upload it to sites like Family Tree DNA or GEDmatch to see if your extended family may be looking for connections. Or you can turn to a service like Promethease for more information on health-related characteristics.
All of these uses have their pros and cons, including some very serious privacy concerns for you and your family. But if you want to try them anyway – or if you’ve already done so – you now know a little more about what happens to your saliva when you send it.