DNA Testing Strategy for Adoptees and People with Uncertain Parentage

Adoptees aren’t the only people who don’t know who their parents are.  There are many people who don’t know the identity of one of their two parents…and it’s not always the father.  Just this week, I had someone who needed to determine which of two sisters was her mother.  Still, the “who’s your Daddy” crowd, aside from adoptees, is by far the largest.

The DNA testing strategy for both of these groups of people is the same, with slight modifications for male or female. Let’s take a look.

Males have three kinds of DNA that can be tested and then compared to other participants’ results.  The tests for these three kinds of DNA provide different kinds of information which is useful in different ways.  For example, Y DNA testing may give you a surname, if you’re a male, but the other two types of tests can’t do that, at least not directly.

Females only have two of those kinds of DNA that can be tested.  Females don’t have a Y chromosome, which is what makes males male genetically.

adopted pedigree

If you look at this pedigree chart, you can see that the Y chromosome, in blue, is passed from the father to the son, but not to daughters.  It’s passed intact, meaning there is no admixture from the mother, who doesn’t have a Y chromosome, because she is female.  The Y chromosome is what makes males male.

The second type of DNA testing is mitochondrial, represented by the red circles.  It is passed from the mother to all of her children, of both genders, intact – meaning her mitochondrial DNA is not admixed with the mtDNA of the father.  Woman pass their mtDNA on to their children, men don’t.

Therefore when you test either the Y or the mtDNA, you get a direct line view right down that branch of the family tree – and only that direct line on that branch of the tree.  Since there is no admixture from spouses in any generation, you will match someone exactly or closely (allowing for an occasional mutation or two) from generations ago.  Now, that’s the good and the bad news – and where genealogical sleuthing comes into play.

On the chart above, the third kind of DNA testing, autosomal DNA, tests your DNA from all of your ancestors, meaning all of those boxes with no color, not just the blue and red ones, but it does include the blue and red ancestors too.  However, autosomal DNA (unlike Y and mtDNA) is diluted by half in each generation, because you get half of your autosomal DNA from each parent, so only half of the parents DNA gets passed on to each child.

Let’s look at how these three kinds of DNA can help you identify your family members.


Since the Y DNA typically follows the paternal surname, it can be extremely helpful for males who are searching for their genetic surname.  For example, if your biological father’s surname is Estes, assuming he is not himself adopted or the product of a nonpaternal event (NPE) which I like to refer to as undocumented adoptions, his DNA will match that of the Estes ancestral line.  So, if you’re a male, an extremely important test will be the Y DNA test from Family Tree DNA, the only testing company to offer this test.

Let’s say that you have no idea who your bio-father is, but when your results come back you see a preponderance of Estes men whom you match, as well as your highest and closest matches being Estes.

By highest, I mean on the highest panel you tested – in this case 111 markers.  And by closest, I mean with the smallest genetic distance, or number of mutations difference.  On the chart below, this person matches only Estes males at 111 markers, and one with only 1 mutation difference (Genetic Distance.)  Please noted that I’ve redacted first names.

Hint for Mr. Hilbert, below – there is a really good chance that you’re genetically Estes on the direct paternal side – that blue line.

Estes match ex

The next step will be to see which Estes line you match the most closely and begin to work from there genealogically.  In this case, that would be the first match with only one difference.  Does your match have a tree online?  In this case, they do – as noted by the pedigree chart icon.  Contact this person.  Where did their ancestors live?  Where did their descendants move to?  Where were you born?  How do the dots connect?

The good news is, looking at their DNA results, you can see that your closest match has also tested autosomally, indicated by the FF icon, so you can check to see if you also match them on the Family Finder test utilizing the Advanced Matching Tool.  That will help determine how close or distantly related you are to the tester themselves.  This gives you an idea how far back in their tree you would have to look for a common ancestor.

Another benefit is that your haplogroup identifies your deep ancestral clan, for lack of a better word.  In other words, you’ll know if your paternal ancestor was European, Asian, Native American or African – and that can be a hugely important piece of information.  Contrary to what seems intuitive, the ethnicity of your paternal (or any) ancestor is not always what seems evident by looking in the mirror today.

Y DNA – What to order:  From Family Tree DNA, the 111 marker Y DNA test.  This is for males only.  Family Tree DNA is the only testing company to provide this testing.  Can you order fewer markers, like 37 or 67?  Yes, but it won’t provide you with as much information or resolution as ordering 111 markers.  You can upgrade later, but you’ll curse yourself for that second wait.


Mitochondrial DNA

Males and females both can test for mitochondrial DNA.  Matches point to a common ancestor directly up the matrilineal side of your family – your mother, her mother, her mother – those red circles on the chart.  These matches are more difficult to work with genealogically, because the surnames change in every generation.  Occasionally, you’ll see a common “most distant ancestor” between mitochondrial DNA matches.

Your mitochondrial DNA is compared at three levels, but the most accurate and detailed is the full sequence level which tests all 16,569 locations on your mitochondria.  The series of mutations that you have forms a genetic signature, which is then compared to others.  The people you match the most closely at the full sequence level are the people with whom you are most likely to be genealogically related to a relevant timeframe.

You also receive your haplogroup designation with mitochondrial DNA testing which will place you within an ethnic group, and may also provide more assistance in terms of where your ancestors may have come from.  For example, if your haplogroup is European and you match only people from Norway….that’s a really big hint.

Using the Advanced Matching Tool, you can also compare your results to mitochondrial matches who have taken the autosomal Family Finder test to see if you happen to match on both tests.  Again, that’s not a guarantee you’re a close relative on the mitochondrial side, but it’s a darned good hint and a place to begin your research.

Mitochondrial DNA – What to Order:  From Family Tree DNA, the mitochondrial full sequence test.  This is for males and females both.  Family Tree DNA is the only company that provides this testing.


Autosomal DNA

Y and mitochondrial DNA tests one line, and only one line – and shoots like a laser beam right down that line, telling you about the recent and deep history of that particular lineage.  In other words, those tests are deep and not wide.  They can tell you nothing about any of your other ancestors – the ones with no color on the pedigree chart diagram – because you don’t inherit either Y or mtDNA from those ancestors.

Autosomal DNA, on the other hand tends to be wide but not deep.  By this I mean that autosomal DNA shows you matches to ancestors on all of your lines – but only detects relationships back a few generations.  Since each child in each generation received half of their DNA from each parent – in essence, the DNA of each ancestor is cut in half (roughly) in each generation.  Therefore, you carry 50% of the DNA of your parents, approximately 25% of each grandparent, 12.5% of the DNA of each great-grandparent, and so forth.  By the time you’re back to the 4th great-grandparents, you carry only about 1% of the DNA or each of your 64 direct ancestors in that generation.

What this means is that the DNA testing can locate common segments between you and your genetic cousins that are the same, and if you share the same ancestors,  you can prove that this DNA in fact comes from a specific ancestor.  The more closely you are related, the more DNA you will share.

Another benefit that autosomal testing provides is an ethnicity prediction.  Are these predictions 100% accurate?  Absolutely not!  Are they generally good in terms of identifying the four major ethnic groups; African, European, Asian and Native American?  Yes, so long at the DNA amounts you carry of those groups aren’t tiny.  So you’ll learn your major ethnicity groups.  You never know, there may be a surprise waiting for you.

FTDNA myOrigins

The three vendors who provide autosomal DNA testing and matching all provide ethnicity estimates as well, and they aren’t going to agree 100%.  That’s the good news and often makes things even more interesting.  The screen shot below is the same person at Ancestry as the person above at Family Tree DNA.

Ancestry ethnicity

If you’re very lucky, you’ll test and find an immediate close match – maybe even a parent, sibling or half-sibling.  It does happen, but don’t count on it.  I don’t want you to be disappointed when it doesn’t happen.  Just remember, after you test, your DNA is fishing for you 24X7, every single hour of every single day.

If you’re lucky, you may find a close relative, like an uncle or first cousin.  You share a common grandparent with a first cousin, and that’s pretty easy to narrow down.  Here’s an example of matching from Family Tree DNA.

FTDNA close match

If you’re less lucky, you’ll match distantly with many people, but by using their trees, you’ll be able to find common ancestors and then work your way forward, based on how closely you match these individuals, to the current.

Is that a sometimes long process?  Yes.  Can it be done?  Absolutely.

If you are one of the “lottery winner” lucky ones, you’ll have a close match and you won’t need to do the in-depth genealogy sleuthing.  If you are aren’t quite as lucky, there are people and resources to help you, along with educational resources.  www.dnaadoption.com provides tools and education to teach you how to utilize autosomal DNA tools and results.

Of course, you won’t know how lucky or unlucky you are unless you test.  Your answer, or pieces of your answer, may be waiting for you.

Unlike Y and mtDNA testing, Family Tree DNA is not the only company to provide autosomal of testing, although they do provide autosomal DNA testing through their Family Finder test.

There are two additional companies that provide this type of testing as well, 23andMe and Ancestry.com.  You should absolutely test with all three companies, or make sure your results are in all three data bases.  That way you are fishing in all of the available ponds directly.

If you have to choose between testing companies and only utilize one, it would be a very difficult choice.  All three have pros and cons.  I wrote about that here.  The only thing I would add to what I had to say in the comparison article is that Family Tree DNA is the only one of the three that is not trying to obtain your consent to sell your DNA out the back door to other entities.  They don’t sell your DNA, period.  You don’t have to grant that consent to either Ancestry or 23andMe, but be careful not to click on anything you don’t fully understand.

Family Tree DNA accepts transfers of autosomal data into their data base from Ancestry.  They also accept transfers from 23andMe if you tested before December of 2013 when 23andMe reduced the number of locations they test on their V4 chip

Autosomal DNA:  What to Order

Ancestry.com’s DNA product at http://www.ancestry.com – they only have one and it’s an autosomal DNA test

23andMe’s DNA product at http://www.23andMe.com – they only have one and it’s an autosomal DNA test

Family Tree DNA – either transfer your data from Ancestry or 23andMe (if you tested before December 2013), or order the Family Finder test. My personal preference is to simply test at Family Tree DNA to eliminate any possibility of a file transfer issue.


Third Party Autosomal Tools

The last part of your testing strategy will be to utilize various third party tools to help you find matches, evaluate and analyze results.


At GedMatch, the first thing you’ll need to do is to download your raw autosomal data file from either Ancestry or Family Tree DNA and upload the file to www.gedmatch.com.  You can also download your results from 23andMe, but I prefer to utilize the files from either of the other two vendors, given a choice, because they cover about 200,000 additional DNA locations that 23andMe does not.

Ancestry.com provides you with no tools to do comparisons between your DNA and your matches.  In other words, no chromosome browser or even information like how much DNA you share.  I wrote about that extensively in this article, and I don’t want to belabor the point here, other than to say that GedMatch levels the playing field and allows you to eliminate any of the artificial barriers put in place by the vendors.  Jim Bartlett just wrote a great article about the various reasons why you’d want to upload your data to Gedmatch.

GedMatch provides you with many tools to show to whom you are related, and how.  Used in conjunction with pedigree charts, it is an invaluable tool.  Now, if we could just convince everyone to upload their files.  Obviously, not everyone does, so you’ll still need to work with your matches individually at each of the vendors and at GedMatch.

GedMatch is funded by donations or an inexpensive monthly subscription for the more advanced tools.


Another donation based site is http://www.dnagedcom.com which offers you a wide range of analytical tools to assist with making sense of your matches and their trees.  DNAGEDCOM works closely with the adoption community and focuses on the types of solutions they need to solve their unique types of genealogy puzzles.  While everyone else is starting in the present and working their way back, adoptees are starting with the older generations and piecing them together to come forward to present.  Their tools aren’t just for adoptees though.  Tools such as the Autosomal DNA Segment Analyzer are great for anyone.  Visit the site and take a look.

Third Party Y and Mitochondrial Tools – YSearch and MitoSearch

Both www.ysearch.org and www.mitosearch.org are free data bases maintained separately from Family Tree DNA, but as a courtesy by Family Tree DNA.  Ysearch shows only a maximum of 100 markers for Y DNA and Mitosearch doesn’t show the coding region of the mitochondrial DNA, but they do allow users to provide their actual marker values for direct comparison, in addition to other tools.

Furthermore, some people who tested at other firms, when other companies were doing Y and mtDNA testing, have entered their results here, so you may match with people who aren’t matches at Family Tree DNA.  Those other data bases no longer exist, so Ysearch or Mitosearch is the only place you have a prayer of matching anyone who tested elsewhere.

You can also adjust the match threshold so that you can see more distant matches than at Family Tree DNA.  You can download your results to Ysearch and Mitosearch from the bottom of your Family Tree DNA matches page.

Mitosearch upload

Answer the questions at Mito or Ysearch, and then click “Save Information.”  When you receive the “500” message that an error has occurred at the end of the process, simply close the window.  Your data has been added to the data base and you can obtain your ID number by simply going back to your match page at Family Tree DNA and clicking on the “Upload to Ysearch” or Mitosearch link again on the bottom of your matches page.  At that point, your Y or mitosearch ID will be displayed.  Just click on “Search for Genetic Matches” to continue matching.

Get Going!

Now that you have a plan, place your orders and in another 6 to 8 weeks, you’ll either solve the quandry or at least begin to answer your questions.  Twenty years ago you couldn’t have begun to unravel your parentage using DNA.  Now, it’s commonplace.  Your adventure starts today.

Oh, and congratulations, you’ve just become a DNA detective!

I wish you success on your journey – answers, cousins, siblings and most importantly, your genetic family.  Hopefully, one day it will be you writing to me telling me how wonderful it was to meet your genetic family for the first time, and what an amazing experience it was to look across the dinner table and see someone who looks like you.



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37 thoughts on “DNA Testing Strategy for Adoptees and People with Uncertain Parentage

  1. Thank you, Roberta. This article is a goldmine of information. I am going to post a link to it in the “Adoptees” forum at 23andme.

  2. As usual an interesting article. I have what I think is a generic question. I am female and tested at 23andme. The result placed me in the H1a3 group. This was a couple of years ago. At that time there were only 5 or 6 of us. Then there were about 10. Now there are only 3 of us in that group. Why? Do you think those people pulled or masked their results for some reason or have their grouping classifications changed? Just curious.

    • They may not have pulled their results. At 23andMe, once you, and your matches, reach 1000 matches, the lowest matches drop off of your list unless you are in touch with and communicating with them…in other words they have authorized communications. If not, they drop off. That may be what happened.

  3. Thanks Roberta. A link is going to all by matches who have indicated they are adopted or don’t know one of their parents. Great information.

  4. You are amazing and I always look forward to your new posts. I have many Wilkes County, NC ancestors so your ancestor articles are of much interest! Thanks so much for sharing!

  5. Oy Vey! Will have to re-read this a few times before I know enough to ask a question … but, Thank You Roberta ….. You never fail to amaze.

  6. Absolutely a great column. I am not so sure how this would work for an unknown Maternal grandfather? I would appreciate any advice. There are no known aunts or uncle, but a cousin and his children have tested. What else could be done?

    • Unknown maternal grandfather is tough. What you’ll need to do is to eliminate others and then take the dnaadoption courses and learn how to work forward. The problem is that you are unlikely to be able to eliminate enough of the others to actually identify the maternal grandfather. I wouldn’t let it stop me from trying though and grandfather isn’t terribly far back. Test as many descendants as you can.

  7. Thank you, thank you, thank you! I am new to the genetic genealogy community and you have helped point me in the right directions to learn where to turn and learn how to use my results. I have taken the Ancestry autosomal test (uploaded to Famiky Tree and GedMatch) and Family Tree mTDNA, basic. I am hoping to locate my mother’s line/family. She was adopted in 1928 from an “unwed mother” home, and we don’t even have a real name to connect to. I have over 300 “matches” HVR1 and HVR2 from the mTDNA but I have no idea what to do with those. And, do I understand that the autosomal matches go by names in your tree as well? If that is the case how in the world do you ever find the parent of an adopted child? Are there other tests that would help?

    • You need to sign up for the courses at the dnaadoption site. They provide instruction as to how to do those kinds of things. If you have know relatives on your father’s side of the family, or if your parents are still living, by all means, test both of them as well. If not, test your father’s siblings, uncles, or their siblings so that you can eliminate people who match you and them as being from your mother’s side of the family. That’s the first step.

  8. Two comments: First, why not discuss the use of the X chromo? I’m new to DNA and my first big hit was a long strand of DNA on the X matching 5th cousins, one male and the other female. Second, isn’t FTDNA autosomal “scrubbed” hence less robust than Ancestry? Of course 23&Me on the V3 was >1,000,000 while the V4 is as you said.

    • I have written several articles about the X chromosome and matching, but it’s certainly not where one would start because the matching pattern is more complex. No, FTDNA autosomal is not scrubbed. Ancestry’s is “scrubbed” in that they phase it and remove what they determine to be areas not relevant to genealogy matching – areas where they feel you have too many matches. 23andMe never tested over 1 million locations. You can see the various numbers on the ISOGG autosomal vendor comparison page. http://www.isogg.org/wiki/Autosomal_DNA_testing_comparison_chart

      • Thanks for catching my typo; it was suppose to be ; the number I have read was 965,000 for V3 while it reads like slightly over 600,000 for V4. Angie Bush, Professional Genetic Genealogist on GEDmatch, ranked V3, Ancestor, FTDNA, and V4 for use on autosomal. While the difference between V3 and V4 was obviously the FDA it was my understanding she said FTDNA also removed health chromosomes (scrubbed – pun intended) and hence came away with a lower number of SNPs than Ancestry. Genetic health issues are very visible in my family – one line has lung problems, another gets cancer, another strokes, and one with high blood pressure. No, I follow your advice and do not help Ancestry. However, my great grandfather probably “adopted” a new name (not spelling reasons, more likely the death of his first unidentified wife) and the family genealogists have spent untold hours and, in some cases, money trying to locate a paper trail but to no avail. We need the best autosomal DNA test available especially since there may be no males left in the line (I’m checking on the last one to see if he’s alive.)

  9. You are amazing. Simple question, direct me to articles if needed: How many matching chromosomes are needed to be considered a person to further study? If you match on one chromosome, do the number of centimorgans indicate the genetic distance of the match?

    • One chromosome is fine. The size of the segment and number of SNPS is the biggest factor. Rule of thumb is 700 SNPs and 7cM but at the vendors, that’s lower than their matching thresholds, so you’re over that if you match there. If you’re matching at GedMatch, that’s another matter. So, I guess the answer is “it depends.” Sorry.

  10. I have done a lot of testing and and would like to share the results and try to do so. I think I have put some on Y-Search, Joined Surname Groups, Haplogroups, etc. How do I download the results from various tests to gedmatch???

  11. Another great article. I was able to find my mother’s parental family late last year. I was one of the lucky ones since I had two close matches that tied into each other that led me on the right path. With a little more research and testing, determined the family, but not the father. There were five sons and only one had children. But without autosomal DNA testing, I would have never found her tather’s family. I started fist by educating myself and one of my resources was your blog. Thanks!

  12. Another great article. I was able to find my mother’s parental family late last year (she was adopted and we knew who her mother was from her original birth certificate). I started with reading your blog and other resources on the internet so that I understood genetic testing. I was also lucky to have two close matches that tied into each other, so after a little more research and DNA testing, I found her father’s family. The family had five boys but only one had known children, so I may never know which brother was my mother’s father, but I wouldn’t know the family without autosomal DNA testing. Thanks for all your great articles.

  13. In trying to determine how exactly a “first to second cousin” is related (he was surrendered for adoption – we have determined that he is related on his and my paternal side), he did the Y-67 test, but he has no matches beyond 12. Is there any point in upgrading to Y-111?

    We finally found a known male 1C1R (to me) who is related on the paternal line, and we are awaiting his results for the Y-67 to compare. Is it reasonable to think that this will help us figure out whether the adoptee’s unknown birth father was descended from a male or female in our family (such as one of my aunts or an uncle)?

    Thank you for this article and for your work.

    • It’s possible, but it’s also possible that the adopted could descend from any other line that feeds into your father’s line. You do sometimes pick up additional matches at 111 because of the greater number of mutations allowed. It just depends on where they fall. However, they won’t be close matches, so I would not recommend that 111 for that purpose.

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  15. I was able to successfully create a ysearch account and get a user ID, but every time I try to search for genetic matches, I get a server error. I even tried manually re-entering the information to search, but still no luck. Is this a problem for anyone else?

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  18. Hi, Thanks for the article. I am an foundling/adoptee using DNA to try to find some answers. One big question I have through DNA is there anyway (with no known relatives but triangulating through distant cousin matches) to know if a match is from the maternal or paternal side for sure? Thanks so much

  19. Could you please tell me the best place to start, I don’t know who my daughter’s Father is. What would be the best test for me to find out what her ethnicity is on the Father’s side and also who some of her other family members may be on the Father’s side? Is there a particular DNA test that can give me this information and if so which test would be the best?

    Thanks, Shelly

  20. I am adopted and I have found my half-sisters. My mother passed away in 1987. My half sisters did not know anything about me. My youngest half sister was 4 months old when her father died. I was conceived almost to the day, a year after he died so he is NOT my father. My half sisters were 2 and 5 when I was born and have no memory of who their/our mother was seeing. We want to do a DNA test to hopefully narrow down who my father could be. We think the DNA test would prove we are half sisters and that we shared a mother. Then we think there may be DNA traits that might narrow down who my father could be. Which test/tests will accomplish this?

  21. How secure is my dna information if I upload it to Gedmatch? I read somewhere that it is not a good Idea? Have you any reassurance? Thanks!

    • Security is a personal choice. You need to read their terms and conditions and understand how the site works. That goes for all sites. I’m fine with GedMatch, but it’s a personal choice that everyone makes for themselves.

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