10 things you didn't know about DNA tests

Wikimedia Commons23andMe is fast-growing consumer genetics company.
  • Home DNA test kits like 23andMe are becoming more popular thanks to their convenience.
  • These tests can often tell you if you have an elevated risk of developing a serious condition later in life.
  • You could uncover family secrets such as that you have half-siblings you never knew about, or aren’t biologically related to your family.
  • If you consent to have your data used in anonymous form for scientific research, you could find that your anonymized data is part of a significant scientific paper in the future.

Home DNA test kits are more popular than ever. While you probably expect to learn some interesting things about your ancestors and maybe turn up an unexpected cousin or three, there are a lot of surprising things you could learn if you take one, as well.

Here are 10 things that DNA tests can tell you that you had no idea about.

If your home DNA test includes a health component, you could learn whether you’re at greater genetic risk for certain conditions and diseases.

In 2017, the FDA approved 23andMe to test for a range of 10 diseases. A year later, the FDA gave 23andMe clearance to tell consumers about their risk of cancer – but as NPR pointed out, it’s important to note that this is meant as a genetic risk assessment, and not any kind of medical diagnosis.

People may or may not want to know this information about themselves – particularly in the case of diseases or conditions where there’s currently no action you can take to prevent it, such as Alzheimer’s.

It’s worth remembering that even if your genetic test results show an increased risk, that doesn’t necessarily mean you will for sure develop a specific condition later in life.

Read more: I revisited my 23andMe results that can now tell whether you may have an increased risk of cancer – here’s what it was like

Health insurance companies can’t legally raise your rates due to genetic health risks uncovered through one of these tests — but life insurance companies might.

vinnstock/ iStockDon’t worry that your health insurance rates will go up because of a DNA test result.

State and federal laws govern health insurers and discrimination against you based on genetic risk information uncovered via tests like this. But as certified genetic counselor Scott Weissman told WTTW, that’s not the case with life insurance companies, which in some cases could make policy or coverage decisions based on that information.

The specific data different companies provide about and to you may differ.

Andrew Burton/Getty ImagesThe data from which your test will compare your results with depends on the company doing the test.

As Business Insider’s Lydia Ramsey discovered through taking several tests herself, the data revealed – as well as individual privacy concerns about how your data is stored, with whom it is shared, and how you can opt out of sharing if you prefer – differs from company to company.

Also, each company that offers home DNA test kits for sale is testing slightly differently, and also relying on a completely different database to which it is comparing your results.

As Gizmodo writer Kristen V. Brown discovered in January 2018, ancestral DNA tests are comparisons between your DNA and that of the current database of whichever company’s test you’ve taken. It’s comparative – and inexact because not all ancestries are equally well-represented.

“We have users around the world but of course there are going to be certain markets that are more interested in genealogy, or have more access to the internet to use our services. This is also the case with DNA testing – DNA testing is better known in the US and interest in DNA testing has exploded in Europe over the last few months. Over the coming months and years we expect to see even greater interest in both of these areas, all around the world,” MyHeritage PR director Rafi Mendelsohn told INSIDER.

Besides learning where your ancestors came from, you might also learn some unexpected secrets.

ShutterstockThere have been multiple instances of DNA tests revealing surprising news.

In addition to learning that your ancestors likely came from a certain region, you might also find out that you have half-siblings no one ever told you about, as a 23andMe user calling herself Marcia told Fast Company.

Some people actively seek this information out, such as adoptees wanting to know their biological families. But for others, it can be an unwelcome surprise that shakes your concept of yourself and your family significantly.

You might also find out that your particular knowledge of what your ethnicity is is different than expected.

Mario Tama/Getty ImagesA vast majority of people have a blended ethnic background.

Rafi Mendelsohn of MyHeritage told INSIDER that in the MyHeritage database, only 0.3% of people have only a single ethnicity – and 99.7% of users have blended ethnic backgrounds that they may have been surprised to learn about.

Of course, as mentioned elsewhere in this piece, each testing company is comparing markers from your DNA sample with those of other users in its particular database. So ethnicities and geographic regions with more participants will have a higher degree of accuracy. If your background is less common, the results might be a lot less accurate across testing companies.

Although narrowing your ancestors down to certain geographic regions makes sense, determining specific countries can be more fraught with potential error.

PixnioThe world’s geopolitics are always changing making it difficult to determine specific countries of origin for people.

Each company doing testing might address this issue differently. As Rafi Mendelsohn of MyHeritage told INSIDER,

“The DNA test looks at both the maternal and paternal side – as it’s an autosomal test – going back a few hundred years – approximately 10 generations. The ethnicity estimate looks at the genetic markers amongst the populations of certain areas and ethnicities. The results that we give reflect the current area.

For example, one of our ethnicity regions is West Asia, an area covering modern-day Iran and Turkey that traces its genetic heritage to the ancient Persians and the Turkic ethnic people, respectively. West Asia is a reflection of the current area but we give an explanation for each ethnicity that illustrates the changing geography and anthropology.”

Your data — in anonymized form — might be part of important scientific research if you consent to allow your testing company of choice to use it that way.

Scientists from Ancestry.com published a paper in the February 2017 issue of Nature Communications that used consenting customer data from the Ancestry.com database to chart migration patterns of different ethnic groups throughout North America. With over 10 million people in its network, Ancestry.com currently has the largest database of customers in the world, Ancestry representative Jasmin Jimenez told INSIDER.

In March 2018, MyHeritage’s chief science officer Yaniv Erlich made headlines when he and his team created a 13-million person family tree using crowdsourced and verified genealogical data from the website Geni.com, of which MyHeritage is the parent company.

Third-party analysis tools have varying degrees of accuracy, which can be especially troubling with regard to false positives for health conditions, such as cancer.

ShutterstockDNA tests often look for mutations in the brca1 and brca2 genes as precursors to breast and ovarian cancer.

When the company behind any home DNA test kit tests your saliva or cheek swab, a raft of raw data from that sample is generated in a laboratory setting. The company then uses some of that information to create a report to send you about your results, but that report usually doesn’t contain everything.

You have access to the raw data, and can choose to send it on to a third-party company for further analysis regarding genetic health concerns. But, as genetic counselor Scott Weissman told WTTW, those results may not be accurate or verifiable and could lead to unnecessary anxiety on your part.

Both you and your sibling could potentially take a home DNA test and get different results.

Flickr / Lisa Rosario PhotographyIt’s likely you and your siblings received different DNA from each parent.

That doesn’t mean you don’t have the same parents. “An interesting presumption that some people make is that if a sibling has taken a DNA test then they will automatically have the same results. This is not the case,” Rafi Mendelsohn of MyHeritage told INSIDER.

Just because you get 50% of your genes from each of your parents doesn’t necessarily mean that you and your siblings each get the exact same 50% of genes from each parent unless you’re twins. If you have blue eyes and your brother has green eyes, you’re still siblings: You just have some visible genetic differences.

Just because you get some health information from a DNA test doesn’t mean you know everything there is to know about potential health issues.

ShutterstockIt’s recommended that you eat healthily and live an overall healthy lifestyle regardless of what your DNA test says.

Learning that you might need to start getting cancer screenings earlier in life than you may have expected can be useful. But genetics aren’t everything – and Dr. Michael Baird, chief science officer of DNA Diagnostics Center talked to INSIDER about the dangers of assuming they are.

He said, “DNA tests – whether samples are collected at home or by a professional – cannot provide all the answers regarding a person’s health. In addition to genetics, there are also lifestyle factors that are important for health and well being. By knowing one’s genetic makeup and incorporating healthy living, one can often improve their long-term health.”

In other words, developing healthy habits like getting enough sleep and exercise, eating healthy foods, and not smoking or drinking too much are important and positive life choices you can make, regardless of what any genetic test might tell you.

Visit INSIDER’s homepage for more.

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