Why don’t the DNA matches match
Julie Matthews is puzzled by her DNA test results:
Why do none of my Y matches also match my autosomal matches? And why are all the Family Finder matches I’m finding ending up being tenth cousins using a paper trail rather than the promised five generations?
Great questions, Julie — the autosomal tests (Family Finder from Family Tree DNA, Relative Finder from 23andMe and AncestryDNA from Ancestry.com) can be really confusing. Let’s see if we can work through these to help make sense of the results.
First, a bit of basic biology for folks new to DNA testing. Every human being has 46 chromosomes — 23 inherited from each parent. Two of those 46 chromosomes determine gender. If the person has two X chromosomes, she’s female. If the person has one X and one Y chromosome, then he’s male. The 44 chromosomes that don’t determine gender are called the autosomes.
So for a Y-DNA test, only the DNA from the Y chromosome is tested, and it can detect common descendants only in a direct male line: father to son to son.
For the autosomal tests, only the DNA from the autosomes is tested, and it can detect cousins both male and female.
And that, most likely, is one part of the answer to why your family Y-DNA matches (I assume that test was done with a brother, uncle, father or male cousin) don’t also show up in the list of those who match you in the autosomal test: a very large number of people who’ve tested for Y-DNA simply haven’t done the autosomal test, and vice versa.
If you look at your list of Family Finder matches, and look in the area under each person’s name, you’ll see some symbols (for email, for notes and, in some cases, for a gedcom if the person has uploaded one). And in some cases you’ll also see some other information — and it’s that other information you want to focus on because it tells you what other DNA testing the person has done.
Y-DNA followed by a number means this person — always a male — has had his Y-DNA tested; the number tells you how many markers he’s tested — 12, 25, 37, 67 or 111. HVR1 or HVR2 or FMS means the person — male or female — has also had mitochondrial DNA (mtDNA) testing done. The letters tell you which test: HVR1 is the least complete, HVR2 the next best and FMS the gold standard — complete mtDNA testing.
If you don’t see any of those indicators under a person’s name in your Family Finder match list, then that person hasn’t done those tests. So the first thing to look at is whether a Family Finder match has even done the testing you hope will match your results. In my own experience, I’ve found that the vast majority of interesting Y-DNA matches to the men in my family haven’t done autosomal testing — at least, not unless I’ve volunteered to pay for it!
The second thing to keep in mind is that Y-DNA and mtDNA don’t change very much from generation to generation, so testing those types of DNA will give you matches that can be very far back in time. By contrast, autosomal DNA changes and recombines so quickly that its usefulness for genealogy pretty much punks out after only five or six generations. (As you’ve found, you can get matches back beyond that but it’s pure luck that that’ll happen.) And this means that a really good solid Y-DNA match can easily be way too far back to show up in your autosomal test matches.
Of course, if you do happen to have a solid Y-DNA match who has also done autosomal testing and doesn’t match you, that can be a clue that may help you figure out how far back the common ancestor might be. In a case like that, it may well be that it’s beyond the time period — five generations or so — where the autosomal testing works best. So even if you never get a double match in both types of DNA, doing both tests is still the best way to go.
On your second question, it’s not at all unusual to find that the paper trail suggests the common ancestry between two matches is further back than the relationship range suggested. One thing that all the autosomal testing companies stress (or, at least, they should stress) is that autosomal testing can help prove you are related to someone else but it can’t usually prove how closely you’re related. Here again, the problem is the way autosomal DNA changes and recombines generation to generation. There’s a terrific short animation on the Sorenson Molecular Genealogy Foundation website — the link is here — that really explains recombination as well as anybody can.
So for this question, too, there are a couple of things to keep in mind. First, the way that these chunks of DNA are passed down is random and it may just be dumb blind luck that you and some distant cousins all got one particularly significant chunk. I see this in my own family results. My first cousin and I both match our uncle, and all three of us have matches we all share, but both my cousin and I have matches in common with our uncle that the other one doesn’t share. Pure dumb luck.
Second, you have to keep in mind that you and those distant cousins may be cousins in more than one line. It was really common for cousins to marry cousins back when the only people close enough to court were cousins! And the more lines you share with a cousin, the more common DNA you’re likely to share so that it’s easy to end up looking like the relationship is a close one when it really means you’re double (or triple) cousins. The concept is called endogamy and it really plays havoc with autosomal DNA results, particularly for populations that were kept in ghettos or whose marriages were limited by law like the Ashkenazi Jewish population. (You can read more about endogamy here.)
And, again, when you see this sort of result, it may be giving you a clue. It’s always worth it, when the paper trail says distant cousin and the DNA suggests a closer relationship, to look for the possibility that you’re related in more than one line.
Sigh… clues, clues, clues. Sometimes I think it’d be awfully nice if our ancestors’ names and lineages were written in the DNA and we could just print them out! Then again… that wouldn’t be nearly as much fun, would it? Good hunting!
I can’t speak to how Family Tree DNA presents their results since I haven’t tested there, but I have tested at 23andMe. In my view, the way 23andMe presents results in Relative Finder leads to the perception underlying the original question (“the promised five generations”).
In my own case, I have a total of 97 matches in RF, and all but 6 are listed either as “3rd to Distant Cousin” or “4th to Distant Cousin”. The word “distant” is vague, so it would be natural for a customer to zero in on the “3rd” and “4th” instead. But I seriously doubt that many of the listed relatives are third or fourth cousins to me, and I would not be surprised if none of them were. If 23andMe presented the results as something like “7th cousins +/- 3 degrees,” that would probably cut down on the mis-perception.
Ruy, the real problem is that any of these suggested ranges is just that: a suggestion. It simply isn’t possible to accurately predict the relationship (except the very closest relationships) so that even 4th cousin is just as likely to be 3rd or 7th as 4th!
Thanks so much – I was reading articles just last night trying to understand why my Y-DNA match is not showing up on my autosomal list. She and I (and our brothers) have done the same tests. Those tests did not offer answers, only more clues – as you say.
Sure sounds like your Y match is just a little too far back to show up on the autosomal list, Pam! It’s a great clue, though!
Thanks for an interesting article on DNA but it continues to raise questions for me. I have tested Y-DNA 67 and am working with several others with similar names and 1-3 genetic distance to see if we can come up with a common ancestor, 10-20 generations. I don’t have a good enough understanding of the DNA tests to know if the mtDNA or autosomal testing would also be worthwhile, I am pretty well documented within the last 5 generations. Would either of these other tests be worthwhile?
Also, my understanding is for Y-DNA testing, a match with no corresponding similar name is not very worthwhile yet familytreeDNA keeps sending me “matchs” at 12 markers with no name similarity. As I understand, absolutely not worth while. Any comment?
(1) Either mtDNA or autosomal might be of help generally but aren’t likely to shed any light on this particular issue (same name, Y-DNA match, 10-20 generations back). Autosomal might help you be more confident as to how far back your Y-DNA matches might be, and it might suggest that the common ancestor is closer than you think. It might also produce leads to more cousins not in your direct male line who might have information to share about your male line. I’m a great fan of autosomal testing, even with its limitations and its frustrations, so I’d do it if you can.
(2) You’re absolutely right: 12-marker matches are about as handy as a handle on a duck’s rear end. You need to change your settings with FTDNA so you don’t get these notices any more. Log in, go to your My Account drop down list, choose Match & E-mail Settings, and change the YDNA 12 matches radio button from Yes to No, then choose Save at the bottom. End of 12-marker match notices.
Judy, you’re a peach! Thank you so much for answering my nagging questions. Endogamy reigns supreme in my family tree so that would explain THAT. And we were very surprised to discover that my grandmother’s mtDNA matches so many Jews around the world given that we aren’t Jewish (although her gg-grandmother is the result of a non-paternal event so anything is possible). Anyway, thanks again!
Glad to help, Julie!!
I have a question. I had autosomal DNA testing done through Ancestry and I did the upload to Family Tree DNA.
When I am looking at matches, knowing I did autosomal DNA testing – if a person that matches me as say a 3rd or 4th cousin did Y-DNA 37 testing, does that mean we would be related through his paternal line ONLY and therefore I should ignore anyone not in his direct paternal line?
Thanks!
Not at all. Your autosomal matches are entirely different from YDNA matches, and they could be anywhere in your ancestry — father’s side or mother’s side for you, and father’s side or mother’s side for your match.
I recently had 3 1st cousins DNA tested. Two of which were the Family Finder and the other a Y-DNA67. In checking the Y-DNA67 test no matches at all showed up. First question would be why would no matches show up at all and the 2nd why wouldn’t the FamilyFinder matches show a relationship to my Y-DNA67 test or vice versa.
If there are no Y-67 matches, it means no relatives in the direct male line who match at that level have also tested, that’s all. It’s not uncommon not to have matches at that level — my own brothers only match each other at that level. But there may be others who’ve tested at a lower level who do match, so be sure to change the reporting level to 37 markers to see if perhaps you have matches at that level. And your other cousins don’t show up as matches in the YDNA match list because they didn’t do the YDNA testing, while your YDNA-only cousin won’t show up in the Family Finder match list because he didn’t do the Family Finder test. You can add the Family Finder test on to that YDNA-tested cousin and, once his results are in, he should then show up as a cousin to the others.
My uncle’s “Y” DNA matches to 3 people with zero deviation, one of whom is a generation younger. This has helped prove the line. My question is according to the chart I’ve seen with approx 96% chance of being related within the last 6 generations, would you expect to see an autosomal match as well?
I might hope for it, but certainly wouldn’t expect it. Although the odds are that the common ancestor would be within the time frame when an autosomal match would be possible, that’s purely a matter of the statistical odds. If your haplogroup is common (if you’re R1b, for example), and the YDNA happens to be stable in your line, the common ancestor could easily be too far back for an autosomal match. Remember, you may not share enough DNA with a third cousin to match autosomally (roughly 10% of 3rd cousins won’t match).
I forgot to add his matches are zero deviation on 67 markers.
This article has been very helpful. I am working on my husbands family tree. We entered the sir name project. I am very certain of his last 5 generations. There have been no “paternal” events or adoptions in that time frame. He took the Y37. There are NO matches at the 37 at all, only 4 at 25 (distance 2), and lots at 12 of course. But there is not a single match in the sir name. The project genealogist said it just might be an undocumented paternal line at this point. Is there any good to upgrading to 67? I’m thinking no, since there is nothing at 37. Also, would family finder give us any clues at all? Since Ancestry’s database is larger and can be transferred would it be better to do that or just add on Family Finder? If we can find even some distant cousins it might give us some clues I’m thinking. I’m certain of no “paternal” events for 5 generations but past that I cannot be certain.
You’re right that it’s unlikely that you’ll get anything more at 67 markers than you have at 37. The reality is, some groups (and some families) just don’t test very often and sometimes we end up with few or no matches. (My own brothers only match each other and no-one else.) If your husband’s haplogroup is something like E, for example, he may well not have any direct male relatives who’ve tested. But turning to Family Finder may well help because it’s much more likely to help him locate cousins from all of his lines, not just his father’s father’s father’s line.
Thank you. I was really starting to be worried i made a mistake in my solving my father’s adoption for his father side. We found two great half sibling matches on my heritage and i wanted to be right so much i didnt do much with the ydna. The ydna has all sorts of different surnames and with two more prevelant. So we upgraded to y-67 even though were still sure about the autosomal findings but ive had questions i havent been able to answer. The upgrade didnt help much and the surname still doesnt match the autosomal surname of the found father. Anyways from yiur infromation it would make sense it wouldnt now since autosomal is more current generations if im understanding? Is there anything ekse that can cause this because ive had others look at the autosomal matches and we confirmed with gedmatch.
There are many reasons why you won’t find surname matches between YDNA testers and autosomal testers, and even among surname testers. But yes, the biggest one is that the autosomal testers are from more recent generations where the surnames will be different (usually because of descent from daughters who married and changed their names).
Hello,
I felt inspired by your article, thank you!
I’m trying to find the father of my late father in law who was born in 1925 using YDNA & autosomal testing. My father in law’s son born 1950 has taken the Y111 & the family finder on FTDNA, as well as testing with Ancestry & uploading to Gedmatch, Living DNA & My Heritage. There is a YDNA match at 67 markers, genetic distance 7. The match does not match on Family Finder, but does match on Gedmatch. The match on Gedmatch is 12 cms. In addition the YDNA matches sister also matches on Gedmatch. They match the same amount, on the same chromosome & segment.
I have built a good research tree from the matches tree. I’m just not sure how much importance I should be placing on 2 matches of 12 cms?
To complicate matters further, my father in law’s mother was also illegitimate so grouping autosomal matches is proving tricky!
You do have a tough case here. But a single 12cM segment isn’t particularly compelling. In that range, the potential that it’s noise (not truly genetically significant) is about 7-10%. Since it’s shared by two siblings, I’d say the chances are pretty good that it is a real genetic segment — but there’s no way to say how far back it comes from. It could have come down easily from a time before genealogical records. This is a situation where you need some patience — and hope for a closer match.
Thank you so much for your advice. This gives me a bit of hope at least. I’ll try to keep an open mind, which is hard sometimes when you are desperate for a breakthrough!