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What DNA Testing Kits Can – and Can’t – Tell You About History, Health


The marketing campaigns for direct-to-consumer DNA testing kits make it seem simple: buy a kit, swab your cheek and ship it off to discover your ancestral origins, connect to distant relatives and even gain insights on your health.

And the marketing is working: the industry has exploded, with several companies competing to add your DNA to their databases of millions. But how much can these tests really tell you about your history and health—and are you ready for the answers?

Certified genetic counselor Scott Weissman and amateur genealogist Barry Love join us to talk about do-it-yourself DNA testing.

Below, a Q&A with our guests. And Love’s top tips for ancestry research.

What do genetic counselors do?

Scott Weissman: I work with individuals and their families who are at risk for genetic disease. I explain what the disease is to the family and the genetics behind it, if there’s a genetic test available to confirm the disease, and if so, talk about implications to the family members and ways to minimize the risk of disease.

For the layman, how do the DNA tests work?

Weissman: Most of the ancestry companies don’t provide disease risk, just information on ancestral background. One provides disease risk information and everyone has the potential of getting the raw data and running it through third party software to get additional information. Essentially, what a lab can do from a saliva sample is look at a bunch of different genetic markers to establish ancestral backgrounds or ethnicities from looking at autosomes. From looking at the sex chromosomes, the Y chromosome in men, they can trace paternal lineage, and they can also do it from mitochondrial DNA that traces maternal lineage.

What can these tests tell you about your health?

Weissman: Right now only 23andme is providing health data, and they give results for three types of health information – reproductive information for about 40 different conditions to determine if you’re a carrier, and information on ten genetic conditions they have FDA approval to test for. The third type is more wellness and trait information that I wouldn’t consider health related – things like athletic ability, how your body responds to caffeine, like that. The type of testing I do is more of clinical genetic tests where these really tell you whether you will or won’t develop a specific disease. One of the conditions [DNA testing companies] test for is Alzheimer’s. The marker they test for does not guarantee someone will develop it, just that their chance may be higher than someone who doesn’t have the marker. I would say if you’re looking for information for potential health, it’s information that can give you a little insight into your health but not all of it may be highly actionable, where you can make a change to medication or lifestyle. For some people it may, but for the vast majority of people it’s not going to.

How reliable is the testing?

Weissman: For the ancestry testing, the information you’re going to get is pretty accurate. Each of the labs use a different reference set that they use to generate ancestry background, so it’s not going to be 100 percent identical [across different tests] but it will be in the general ballpark. For the 23andme, the ten conditions they have FDA approval to test for are very accurate. They had to go back and prove that their tests work and validate data they were giving to patients to get approval. For people who take the extra step and run raw data through third party software, it’s not highly validated at that point; it can be a little more concerning. Sometimes the results are proven not true, or can be falsely positive, they may say someone has a specific mutation that they don’t, or for a certain gene there may be 10 or 20 different markers that show up so they think they have all 10 or 20 mutations in that gene. So how those results get interpreted is really critical to this process.

Are the tests secure?

Weissman: My understanding is that it’s gotten more secure, where for 23 and me they have research consents that you have to sign if you want to participate in research. If you look through the terms and agreements, they essentially own your DNA, and while they could in theory sell it to third parties, they can really do whatever they want at that point. Typically they’ll anonymize it, but there are people that believe that if you know someone’s genetic makeup you could backtrack who they are. For the vast majority going through this testing, I don’t think there’s a lot of adverse that can happen.

How can genetic counselors help?

Weissman: If someone comes across something on a report, I would reach out to a genetic counselor to set an appointment and talk about what condition they’re concerned about, to take a personal and family history looking for signs and symptoms with the individual that would fit, determine what’s the likelihood that they have it, is there any reason to do a confirmatory test. If it turns out they have the condition, then talk about what are the next steps, what do you tell your doctor, what kind of blood work is necessary, what imaging tests does someone need to do, what does it mean to other family members, so they can be aware of potential risks. Basically sitting down and breaking down the generic jargon into an understandable format so they can get info in an understandable and practical way.

What are the risks of DNA testing?

Weissman: I think more so for the ancestry testing, there’s a lot of good information that can be gotten out of doing it and looking for where your family comes from, but sometimes this information can lead to unexpected family information—discovering half-siblings, or people find out that there was an egg donor or sperm donor, in some extreme cases they’ll find evidence of incestuous relationships. So it’s really important to go into these things with eyes wide open that this can be a byproduct of this sort of testing, which is something that they don’t really talk about in the marketing of the tests. Most people aren’t having the conversation with a genetics professional before doing this type of testing. With some of them you have to opt in to share your info, but you’re not thinking about it being a possibility. For the health tests, I would say it’s really about better understanding what type of information they’re testing for. A lot of people don’t really want to know about risks for disease that you can’t do anything about. After the conversation, most people choose not to do it because they realize healthwise there’s not much you can do about it. But for some people, they want to know for purposes of insurance planning, financial planning, so if this eventually happens it doesn’t become a financial burden to their family.

What does the Chicago Genealogical Society do?

Barry Love: The Chicago Genealogical Society’s members range from nationally known professional genealogists to absolute beginners who all share a passion for genealogy. The mission statement is to preserve documents and history of people related to Chicago, but Chicago has been a hub of the Midwest forever, so the research carries out into the Midwest and far beyond – most of my family is from the Detroit area and the South but there’s a lot of resources in Chicago and the Midwest. Chicago has a number of great institutions, like the Newberry, Chicago History Museum, a lot of local neighborhood historical societies, the Chicago Public Library especially the Sulzer Regional Library, you can find some heritage museums for various ethnic groups, so it really depends on what your focus is.

Is the Genealogical Society seeing a surge in interest in ancestry research?

Love: Yes, especially among younger people, which is fantastic. The advertising and television shows get people kind of excited – they’re a little misleading in terms of how easy it is, but that’s the first step and hopefully they’ll get passionate about it and then they’ll pursue it more.

How did you get started in ancestry research?

Love: The 2010 census. I was filling that out and it asks about ethnicity, and I thought, “Caucasian, pretty bland.” It struck me that I should know more than “I’m a white guy.” So I started playing with Ancestry.com, and when testing came around, I thought, “this is cool, let’s see what this does.” I was skeptical, so I tested with all the companies, and as I learned more, realized how powerful the tools they use are.

Are you seeing a lot of people getting some unexpected results in their DNA testing?

Love: There’s a group of us that are focused on genetic genealogy. One asked his sister to test and discovered that she’s a half-sister. And he’s in his late 60s, early 70s, so he has to decide, does he tell her? There are a lot of ethical questions. Professional genealogists are defining guidelines now because it’s a new and expanding field. As these databases get so big, we’re closer to 7-8 million in Ancestry.com’s database, you’re going to find more matches, so you can find potential half-siblings that you never knew about. It’s going to become a much bigger question and it raises really interesting questions about what’s the definition of family? How does that change the family dynamic, your impression of who you are? There are a lot of implications.

In your opinion, is there an appropriate level of privacy in these tests?

Love: It depends on the company. They’re getting good about having opt-in and opt-out options. Some people will test because they want the ethnicity chart, so there’s an option to only do that and you’re not part of the pool. You have to decide what your goals are and how private you want to be. 23 and me does health testing as well, and they’ll ask you to do opt-in surveys on genetically based disease and developing therapies. Some people have the idea that they’re going to make millions off my DNA, but the way I see it, if they discover some great thing because I’m some rare genetic mutant, awesome.

Barry’s Top 10 Tips for Ancestry Research

1. If cost is a major concern, wait for a sale. Competition is fierce, and sales are frequent. Almost every holiday is an excuse for a sale.

2. Be patient. Test processing can take several weeks.

3. Be prepared for surprises. Few people think there will be surprises in their family, but it's quite common.

4. Test the oldest generation first, before the opportunity is lost.

5. Fill out at least a basic family tree. Other people will do a lot of work on your behalf, but you must help get them started. Fill out at least direct lineage beyond living generations. Living people are not visible to others.

6. Don’t get discouraged. It’s rarely as easy as it looks on the TV shows, and every family has brick walls. The challenge makes it more rewarding. 

7. Don't be shy. Seek help. Genealogists are friendly people, and they love to share their knowledge and make connections. Chicago has great genealogy resources. The Chicago Genealogical Society, the Newberry Library, the Chicago History Museum are great places to start.

8. Be kind to those that reach out to you. You're family, even if you don't know the relationship yet.

9. Upload to GEDMatch.com. This free site offers fun, powerful tools, and allows comparisons across testing companies.

10. Y-DNA - more markers does not mean more matches. If you're focused on your paternal line, start with the 37-marker test. Upgrading to more markers will mean fewer matches, not more.  Upgrade later if you have too many close matches at the lower marker level.


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