Having given these questions much thought, I thought a good starting point would be to look back and start researching my own family history. When I was young I always thought I was 100% British. My Dad was born in Edgware and my mum in Hampshire. Of course, none of us are truly 100% British and as I got older I learnt that my Dad had Russian great-grandparents on one side and German on the other, and that my great grand-parents on my mother’s side were Greek. So I suppose this is when I started considering how much of my identity was defined by my family history.
Many people who submit their DNA to a direct-to-consumer company also upload their raw information to public databases like GEDmatch, which law enforcement can access. People upload their raw DNA data after taking another test, like those from 23andMe or Ancestry, to several open online DNA databases. Most companies do not release database information to law enforcement. However, a recent study found that, using publicly available data, it's possible to identify up to 60 percent of Americans with European heritage via third-cousin-or-closer DNA.
In fairness to 23andME, it leaves it up to the customer to unlock the more serious results – or not. When I unlock mine, I discover that, while I’m not genetically predisposed to such things as the BRAC1 or BRAC2 variant, Parkinson’s or MS, I have one of the variants for late-onset (mid-80s) Alzheimer’s. However, I don’t have any other markers for Alzheimer’s or family history or conditions associated with it or anything else listed in the rather lengthy disclaimer, which also stresses that it’s not a diagnostic result and to seek further advice from your GP if you are concerned.
There are two questions I would want answered through DNA testing. I never knew my mother but was told my great grandfather was “full blooded Cherokee Indian” and my six year old grandson is told by father “he is direct descendent of the Zulu nation”. Their words! Which DNA testing company would be able to answer these questions? I’m a little confused with the info presented. Thank you!
If the company responsible for running your test is sold, whatever you signed loses significance due to the privacy policies of the company. Despite most of these privacy policies stating they will notify you of any changes, you would have to keep in constant contact with the company to ensure you were actually aware of these changes. The people willing to do this would be far and few between. Unfortunately, even if your name is not located within the database, this does not mean other databases cannot be used to determine your identity. In one specific case, a woman had a DNA test run. She found out she had a half-sibling. Although she was very excited about this news, this type of information would devastate numerous individuals.
Of course, most DNA used by law enforcement in the U.S. does not come from direct-to-consumer DNA tests. The federal government and many states collect DNA samples from suspects of violent crimes after arrest or due to probable cause. These samples are added to the Combined DNA Index System, or CODIS, which is a national database for forensic information.

The most common type of DNA test is an autosomal test – ie the ones you see advertised all over the place. These tests give you both ethnicity results and matches – not just cousins but whoever you’re related to who have also tested with the same company. Ethnicity results are a result of both parents and cannot be separated with a single autosomal test. Ancestry and FTDNA are great picks and both will suit you well. The main difference in my opinion is that Ancestry has a much larger customer database, which means you’ll get more matches. And yes,… Read more »
Gteat article! Thank you so much. I am Jewish American. Both sides of my family immigrated from Eastern Europe/Russia about 5 generations ago. I would really like to try and find out more about exactly where they came from, identify potential living and deceased distant relatives in the USA and abroad and ultimately start creating an extensive family tree. Which test would you suggest?
This is a large amount of data not being used by services testing DNA. There are millions of SNP’s contained in your DNA. This type of testing only looks at specific variations. This requires between 100 and 300 AIM’s. This is a small fraction of the SNP’s differentiating DNA. This means if your test stated you are fifty percent European, it means only half of your SNP’s appear to be European. Another issue is certain markers used for ancestry information for any given test are only derived from either your Y chromosomes or your paternal line or your mitochondrial DNA or maternal line. When these markers are used, your test will be less accurate. Another flaw is the DNA testing services are obtaining DNA from the current populations in specific regions. This makes unsubstantiated conclusions that the people living in these areas hundreds of thousands of years in the past have had the same DNA for all these years.

I’ve been working on my family tree for decades. When I took the AncestryDNA autosomal test, the ethnic results matched my expectations, with mild variations. I knew my mother was of completely Irish heritage, but I came up 58% Irish, so apparently some of Dad’s British ancestors were Irish, not English, for instance. The section that matched me to other DNA test-takers was also accurate. I recognized a couple of my second cousins listed there. Other people had taken the test but hadn’t created a family tree, so there was no point in contacting them to figure out which ancestors we had in common. Be sure you’ve done some research on your own family–these kits do NOT tell you where you grandparents came from, or their occupations, or their names. They tell you how much of your DNA is common with certain nations or areas. I know I have some Germanic ancestors, so when my kit said “14% West Europe” and that turned out to include Germany, France, Netherlands, Belgium, Luxemburg, and Lichtenstein, it made sense.
“My concern is that more and more of these tests are being put out, and people are being persuaded to have these tests done, and they get results back that are very often of very low value and dubious helpfulness,” she says. “And often people are told to go to see their GP and that then places a direct stress on the NHS, at no cost to the company. The companies make their profits and walk away, letting the NHS sort out all the fallout, the push-back, from the test results, in a way I find absurd. Why should the NHS have to prop up the problems that these companies create?”
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