Reliability of DNA Matches in At Home DNA Tests

CeCe Moore, founder of The DNA Detectives explains why users of at home DNA tests should take DNA matches seriously, and how she’d like to work closer with the forensics community to use her skills to identify Jane and John Does.





Hi, I’m CeCe Moore, and I’m a genetic genealogist. I’m the founder of The DNA Detectives and the co-founder of the Institute for Genetic Genealogy.

We have lots of people who come to my group and say, “I matched with someone at the top of my list that shares a ton of DNA. I didn’t even know I was gonna get matched.” There’s two parts to these [at home DNA] tests. There is the admixture percentages that most people test for, but there’s also the DNA matching part of it that all of the major companies do. The commercial companies that I use – all of them have match lists. 23andMe is the only one that you can opt to being matched to other people. The other three, it’s automatic. So, be prepared – it’s not just percentages. There’s much more to these tests. And they’re much more reliable, by the way.

People put a lot of stock in these percentages when they probably shouldn’t, and they’ve read some articles that say they’re not as reliable as you might think. Then, they extrapolate that to believe that the match lists aren’t [reliable]. So, they get a half-sibling match and they say, “Oh, it’s not real, because I read an article saying these companies are not reliable.” Believe me – if you get closely matched to someone based on how much DNA you share, that is a very solid part of this science. It’s two completely different things. Ethnicity (or admixture) take with a grain of salt. If you get a strong match… Parent/child we’ve seen people reject! That is an absolute. If you get a parent/child match, that’s real, and you better take that seriously. So, I hate to see some of the media stories get misinterpreted to have people reject close family members, because they think that the science isn’t reliable. The matching part of this is extremely reliable. If it weren’t, I wouldn’t be able to solve cases every day based on it.

I would like to work more with the forensics community. There are challenges in that, but I’m hoping we’ll find ways to work around that, because what I do is very much applicable to forensics and I’m particularly interested in working to identify some of those Jane and John Does more so than law enforcement. I’m a little bit more hesitant to try to identify a killer. As much as I want those solved, there’s a lot of ethical questions and a lot of differing opinions in my community about whether we should be leveraging our databases for that. But, for identifying deceased people for their families so they can get some peace, that’s something that’s very much along the lines of what I do now (just kind of reversing it a little bit). So that’s where I really think my focus will be.