DNA analysis has a very important and scientifically acknowledged role to play in forensics and medicine and law (for example) but the analysis provided by most commercial organisations selling to the general public and claiming deep genealogical insights is little more than modern day snake oil - bunkum (at least to date). See for example DNA ancestry tests branded 'meaningless' and Genetic Ancestry Testing.

Many companies now offer to tell you about your ancestors from a DNA test. Adverts for these tests can give the impression that your results are unique and that the tests will tell you about your specific personal history, but the very same history that you receive could equally be given to thousands of other people. Conversely, the results from your DNA tests could be matched with all sorts of different stories to the one you are given: you cannot look at DNA and read it like a book or a map of a journey. Sense About Genetic Ancestry Testing.

I have no doubt many will disagree (such tests have already been taken by an estimated over 12 million people) and I do not dispute that useful, reliable results have often been achieved that could not have been in any other practical way. Amongst such may be included Christopher Franklin that, though not for the purposes of genealogical research directly, was a familial comparison.

The tag is at present our fourth most popular tag and I believe the matter should be on topic here. However the Stack Exchange family of sites has an excellent reputation and quite rightly strives for high standards. The connection gives much credibility to what many scientists say are as meaningful as a horoscope.

Without seeking to make the subject off topic I feel we have an obligation at least to provide information that warns users of some of the dangers. For example the ones expressed by Scientific American in their article 23andMe Is Terrifying, but Not for the Reasons the FDA Thinks.

Maybe this meta post could be considered adequate for such purposes but, given what seem limited options within the SE format, would a small caveat in tag wikis be appropriate (plural because there are several, see the bullet points in the tag wiki for DNA, and I do not seek to single out 23andMe)?

* Title borrowed from Live Science.
† The article is dated 2010 and since then the jury recommended that Lonnie Franklin Jr. should be sentenced to death.

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    Is what you are hoping from this discussion some suggestions for how to improve the tag wiki for DNA, or something else? – PolyGeo Apr 30 '18 at 22:12
  • Perhaps re-read your post, and see whether you can think of how it might be edited to make what it seeks clearer. I may be the only one not able to get that, in which case ignore my comment, or I may be just the first one to say so. I'm sure you are raising a valid topic, but I'm looking for a better understanding of what you seek in any answers that may be offered. – PolyGeo Apr 30 '18 at 23:30
  • Re-reading your post again I think what you are asking is "Do we just need a warning added to the DNA tag wiki, and the tag wikis of the tags listed as dot points there (if so, what words for the warning?), or do we need something stronger to be implemented (if so, what?)?" – PolyGeo Apr 30 '18 at 23:38
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    I have resisted downvoting this, but I fail to see any real specific criticisms of the use of DNA for genealogy here. What are the specific warnings we should have here? We do not test DNA, nor do we actively promote DNA testing. DNA is a powerful tool for confirming or refuting genealogical relationships, and it is well established that any ethnicity estimates need to be taken with a large pinch of salt. – Harry V. May 1 '18 at 2:31
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    Citing assertions made in articles from the news media rather than a scientific journal is bad enough, but seriously, you're going to invoke the opinions of a journalist that were published in 2007 as if they were relevant to the industry today? – Jan Murphy May 3 '18 at 1:46

Having read your question several times, I'm still finding it hard to understand the point you're trying to make, but let me take a stab at paraphrasing your question and then responding to that.

Paraphrasing your question:

DNA analysis is important in some scientific/legal contexts but rubbish in a genealogical context (except when it isn't).

Here are some 5 year old references to support this thesis. (And an 11-year old one).

DNA testing ought to be on topic here, but we should warn people that it's rubbish. And that the companies doing genealogical DNA testing are collating vast sets of personal data that they intend to exploit.

We must do something.

My response:

DNA testing is a valid part of the genealogy toolkit -- it can confirm a relationship suggested in a paper trail, or identify avenues for exploration -- looking at the last five-ish generations. I believe we should be supporting and encouraging this use of the technology (but see later for caveats).

Almost all the genealogical testing companies will purport to tell you 'where your ancestors came from' or 'your ethnicity' (your genetic admixture). In the vast majority of cases, the results are so generic as to be meaningless -- they can only be as good as the reference populations the relevant testing company uses, and the information provided by members of that sample about their countries of origin. We almost always include this information in answers to questions about ethnicity testing -- at best it's an (expensive) parlour game if ethnicity testing is the only reason for doing a DNA test. (There are some companies with better-constructed reference populations -- e.g. livingdna.com -- but they are the exception rather than the rule and tend to focus very narrowly).

Almost all genealogical testing companies will seek your permission (with more or less clarity) to use your data for purposes you might not want it used for -- in this they're no different from social media companies, banks, insurance companies... any organisation to which you hand over your information, although the uses to which genetic information can be put are different and some people might think this warrants special handling.

What should we do?

Most people come to us with questions after they have had their test done, so much of what we can do is only 'covering our backsides'. However, what about:

  1. A canonical question about the value of genetic admixture testing, explaining why it is probably not useful for genealogy purposes. (If somebody still wants to waste their money, that isn't our problem). We might also want to roll up in this some stuff about interpreting the results, so we can close a lot of questions about that as duplicates.

  2. A canonical question about the risks of DNA testing (I did ask one last year Explaining risks when seeking DNA testing by cousin? but got very little response). This could cover: privacy risks, risks of finding out stuff you really didn't want to know (or that your family didn't want to know), and (new kid on the block) risks of any criminals in your family being identified via DNA. We should include advice about how to manage those risks.

  3. A canonical question about the real value of DNA testing in genealogical research, to enable people who want to use it 'properly' to do so in an informed manner and without underestimating the amount of work required.

We should support any points we make with up-to-date reference material.

I don't suggest using the tag wiki as so few people ever read them.


My opinion is that genetic genealogy is simply another tool in the toolbox, and the same concerns that we have about DNA also apply to what people might now call 'paper-trail' genealogy. We now have the capability to analyze DNA much faster than we could before. And because of technological advances, we can now gather information about a person much faster than we could before. Saying this is a "DNA problem" is making a distinction where none exists.

This particular question is poorly thought out because it muddles two separate issues -- the legitimacy of ethnicity estimates, and the privacy and ethics concerns of participating in DNA testing for genealogy.

The 'Bad Science' question

For the problem of ethnicity estimates, I would ask in turn, how much is it our responsibility to correct the mistaken claims of a company's marketing department?

We can already see from previous discussions how resistant many hobbyist genealogists are to following the already-known genealogical standards such as the BCG's Genealogical Proof Standard, the principles of Standards and Good Practice in Genealogy outlined by the Society of Genealogists, the Guidelines for Sound Genealogical Research outlined by the National Genealogical Society, or guidelines created by other reputable genealogical organizations and individuals. They complain that following standards is "too much work" or rebel against academia.

Genetic genealogists can get clues from ethnicity estimates that can be combined usefully with their 'paper trail' research. The problem is that doing so requires a level of sophistication and understanding of the data that most hobbyist genealogists don't have. This is not any different than hobbyist genealogists who don't want to educate themselves about doing paper-trail genealogy. They think they can just follow hints, cherry-pick the information that suits them, and they don't want to use the elements of the GPS to improve their research, because that is "spoiling their fun". Why should we single out DNA for needing this extra caution?

The Privacy problem

For the issue of privacy/ethics, we could handle the issues in one of two ways:

Canonical Questions

With 'canonical questions' (as previously posed). The second question proposed in the previous answer might be broken out into questions such as the following:

  1. How can my DNA be used by the police?
  2. What are the ethical considerations of participating in DNA testing?

In the canonical answer we could collect links to blog posts such as Roberta Estes' recent post The Golden State Killer and DNA and Judy G. Russell's The Bull in the DNA China Shop.

Adding to the Privacy rule section

Roberta Estes' post The Golden State Killer and DNA gives such a comprehensive overview of how DNA can be used to trace people that it might serve us well to add it to the site's privacy policy, with a disclaimer that if you are considering taking a DNA test, you should read this article first.

In any case, if we undertake this task, I would want to see links to references written by scientists, lawyers, and genetic genealogists. It does no good to steer people to articles written by journalists, especially third-party "scientists say" articles where the author doesn't understand the science or doesn't understand genealogy, such as the articles linked to in the questions.

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    No, I understand quite well that the ethnicity estimate is the 'bait' which companies use to get people into their databases. Your question didn't make that explicit. It is muddled. – Jan Murphy May 3 '18 at 22:20
  • I'm not in favour of breaking out the canonical questions -- as they're effectively for 'newbie' to DNA testing, I'd rather they got the information in a few chunks not many. – ColeValleyGirl May 4 '18 at 7:55

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