# When the DNA says your parents are related

One of the first things I do when helping someone with their DNA results is to check if their parents are related. This can explain unusual patterns of matches, for example, all seemingly from one side.

GEDmatch.com has a nice tool called “Are Your Parents Related” (AYPR) in the”Analyze Your Data” blue panel (middle right of page) which looks for places in the specified kit where the DNA is identical on both chromosome pairs, maternal and paternal. This happens when you inherit the same segment of DNA from each parent because they are related. We call this a homozygous run which is a fancy way of saying a stretch of identical DNA on both sides.

CeCe Moore specializes in helping people who make this discovery. Click here for the informational brochure she helped Brianne Kirkpatrick, genetic counselor, create. It includes where to get emotional support.

My goal is to help you figure out what the DNA means yourself. Can you deduce what the relationship of those parents is? Well a very simple rule of thumb is to multiply the shared DNA from AYPR tool by four and look up that new total at the DNA painter calculator for the possibilities. Then do further family DNA testing to confirm.

Why does this work? Let’s look at the numbers. Suppose your parents share 25% of their DNA. They will pass about half of that to you, so 12.5%. However only about half of that will be the same DNA so it will show up as about 6.25% on the AYPR tool.

Look at the image. The total is 215.3 when you multiply by 4 you get 861.2. You might look that up before you read on …

I was consulted on a case where the father was found to be not related via DNA and the secret family story was that the biological father was actually a cousin of the mother. First cousins share 12.5% of their DNA. They each pass about half of that, so 6.25%, to their child. About half of that half would be the same DNA from both parent, 3.125% or about 233 cM. The image of the matching chromosomes is shown above and the number summary is:
Largest segment = 46.7 cM
Total of segments > 7 cM = 215.3 cM

These numbers suggest that family story is true. Further family testing, for example of the child of the first cousin and suspected Dad, will confirm it.

First cousin marriages were quite common in the past and are legal in many states. Uncle/niece marriages were also common in some communities. People from very endogamous groups will often have distantly related parents and it may or may not show in this tool. My Jewish husband actually shares 13cM of X DNA with me and my aunts, probably from quite far back on my German Jewish grandad’s line and his Galician descended mother’s line.

Now to look at the more closely related cases. Please remember, if this is like your case, it is no reflection on you. If your parents are related your DNA is probably just fine. Plus it will have no effect on your own children’s DNA.

In another case, a woman contacted me and told me that the rumor was that her Dad was her mother’s half brother. Does that fit with the numbers below and the image to the right?:

Largest segment = 49.4 cM
Total of segments > 7 cM = 290.0 cM

Multiplying 290 by 4 you get 1160. While this number has not been observed by Blaine’s project for half siblings, it is theoretically in range.

Further testing of family members confirmed this rumor.

Then there was the case of the fellow whose father was also his mother’s father. CeCe Moore figured that one out. Click here for his write up of his story.

These are his numbers and his image is to the left:
Largest segment = 77.3 cM
Total of segments > 7 cM = 756.7 cM

Multiplying by 4 you get 3026.8 … which falls between the normal sibling range and a parent-child as expected  …

[UPDATE 26-Jul-2018 at 13:00: A parent passes half of what they got from each of their parents to a child thus about 25% of that child’s DNA is from each grandparent. The parent/grandparent passes the new child a different 50% than they gave the child/parent so the DNA would end up being about 18.5% identical (half of 25 plus half of 12.5). In the case of full siblings, since about half of their shared DNA is the same on both sides for them, the resulting identical DNA is not half of the shared half so 12.5%, but all of the 12.5% that was the same on both chromosomes plus half of the remaining 12.5% so more like 18.5%, thus it overlaps the other case]

How can you tell the difference between the child of full siblings and the child of a parent-child relationship other than emailing CeCe? Andrew Millard, whose simulations Leah Larkin often blogs about, came up with the idea of mapping the shared segments. If they are all from one side, then it is the parent-child case.

[UPDATE 27-Jul-2018: Leah Larkin has shared her analysis of a case where the mother was known and the question was whether the dad was her father or brother. She uses several of Andrew Millard’s simulations:
http://thednageek.com/gordon/ ]

The technical term for lots of shared segments between one’s parents is “high ROH” which sounds much better than the “in” word. If this is your case, please read the brochure above and find yourself some help and support. You are okay, really, it’s not your fault.

Remember multiplying by four just gives a rough estimate. The result is likely to fall in more than one range, so further family testing is best for sorting this out.

[Everyone whose data was shown here has given permission for this usage. No names or kit numbers are shown]

## 131 thoughts on “When the DNA says your parents are related”

1. Cindy says:

What a clear and easily understandable way to explain this. I have never seen an explanation on this. Thank you Kitty!!!! Now I understand how to read the numbers.

2. John Souza says:

Great article! I especially like the last chart. LOL! Oh, wait, maybe because it’s mine? hahaha

3. Julie Hahn says:

I’m hoping this will allow me to clarify for an adoptee I’m helping. CeCe has already confirmed it’s either the BM father or brother. The adoptee does want to know the truth.
I’ll be working on this later today.
Thank you!

4. Kitty says:

An important comment by Kathy Johnston on FaceBook (who gave permission to publish here) somewhat rephrased:
Many people expect to see these identical segments when their parents are closer than 4th cousins. Just because this comparison is negative does not mean they are NOT related within a genealogical time frame. … The AYPR tool cannot rule out distant and even some closer relationships. Even if the parents share more than one segment with each other, these matches may not get passed on to the child.

5. Thanks for the clear explanation that shows how to determine the estimated relationship based on ROH. My grandparents were 1st cousins once removed. My dad and the two siblings that I’ve tested have ROH results that reflect that and the 1C1R is the estimated relationship with your method of calculating.

I’ve always known about this and it was never a disturbing fact. At family reunions I remember hearing a relative say, “Oh, yes, Uncle Rob married cousin Erie.” It was said in the same manner as someone would say, “They make the most delicious pecan pie!” When I tell other people about it, they don’t think of it the same way, though.

I tell you, though, it can be very confusing when dealing with DNA matches. Because not only were they 1C1R, they were also 2C1R and 2C2R in such a way that all – every single one of them – of my grandfather’s family lines end up in my grandmother’s family tree. They even have the same maternal haplogroup!

I wrote a blog post about the entangled family lines: http://history.jciv.com/2016/09/entanglements/

• Kitty says:

I enjoyed your blog post. This used to occur alot more than people realize!

6. Leslie says:

This is fascinating! It also makes me wonder if I can use my DNA analysis to confirm or disprove a discovery I made through genealogical research. It involves my father’s maternal grandparents. There are no rumors (at least none to my knowledge), but when I found my ggf’s immigration record, it said he was coming to the US to live with his cousin. I happened to discover that this cousin was my ggm’s uncle (her mother’s brother). I wonder whether he used “cousin” as a sort of euphemism on his immigration records, or if they truly were cousins. I haven’t yet been able to find an answer by using standard genealogical methods. Is there anything I can check for in my DNA that may help solve this mystery?

• Kitty M Cooper says:

Unlikely you can prove anything via DNA that far back unless you can compare lots of descendants of his parents to descendants of her parents.
Also cousin may have been a 2nd or 3rd or… Best to try and look I the records

• Leslie says:

Thanks, Kitty!

• jennie burrows says:

in some cultures, every relative is called a “cousin”

7. Barbara Shoff says:

Kitty, you have helped many by sharing this information. Outstanding post.

8. Paul says:

What type of DNA testing do you need to get the information that would reveal something like this. There’s so many tests and they get fairly expensive. I’m not interested in finding anyone.

• Kitty says:

Paul –
Any of the personal genome tests discussed on the following page, Ancestry, 23andme, My Heritage, or familytreeDNA will have this information once you upload the results to GEDMATCH:
http://blog.kittycooper.com/dna-basics/dna-testing/

• Paul says:

Ok, thank you.

9. Kiki says:

So fascinating! The possibilities are endless, huh?

There is a rumor that my maternal 1st cousin (female) could be the daughter of my maternal full aunt and A) (hopefully) my cousin’s father, the man that raised her, B) our maternal full uncle (full brother-full sister incest), C) our maternal full grandfather (full father-full daughter incest). Gross, I know. My cousin, my mother and I have all done 23andMe.

My cousins parents are deceased, as is our maternal grandfather, so they cannot be tested. The maternal uncle in suspect is alive, elderly and has no interest in genetic testing.

I show up as a solid 50% identical to my mother across every chromosome, as well as with my father. My cousin shares 2127cm on 54 segments with my mother, which, according to ISOGG, puts them at the high end of being aunt-niece or half-siblings. On some of the chromosomes they are 90% half-identical. They share 126.87cMs on the X chromosome, ~70% of that half. However, my cousin and I share 0 of the X chromosome, yet I am a solid 100% identical on the X I got from my mom. How I can share 100% of an X chromosome with my mom, my maternal cousin shares ~70% of an X chromosome with mom (my cousin’s full aunt), yet my cousin and I share 0%? Explanations? Any input is helpful! Thank you

• Kitty says:

Hi Kiki,
What does the “are your parents related” tool find on your cousin’s kit? That will tell you if there was incest involved.
As to the X match, your mother has TWO X chromosomes that is what makes her female but she only passes ONE X to you, which is usually a recombination of her two Xs. It just happened that she passed you X that does not overlap with the X she shares with your cousin!

• Kiki says:

Thank you so much, Kitty. Got it, I think! So the X my mom passes to me is NOT an exact copy of one of her Xs, but a combination of her Xs? Where as the X that my father passes on to me IS an exact copy of his X? Unfortunately (or maybe fortunately) my cousin does not want to use the “are your parents related” tool. She’s healthy and happy, her offspring are healthy and happy. Will it really matter 50 years from now? Maybe it’s better to let sleeping dogs lie. I’m still super curious, though. 🙂

• Kitty says:

If her parents are related it does not mean she will have health issues and her children rate to be fine. It usually takes generations of inbreeding to cause serious problems. The issue is when you get two copies of a deleterious gene, you are stuck with it …
You can run the AYPR tool on her kit number if you must but then you may be holding a secret which can be hard on you. So my advice is leave it alone; it’s up to her.

• Kiki says:

Yes, I agree. My thoughts exactly. I’m going to let this one go. Satisfying my morbid curiosity isn’t worth causing anyone heartache. Thank you for all of your information on this whole DNA thing. So fun and interesting!

• Bob says:

Sooooo….

My AYPR x 4 comes to 3505.8. I’m gonna go out on a limb here and assume my father is my grandfather. Does that sound right or could it be an uncle?

10. Alan says:

Yes a valuable tool and article!! I have 56.9cm on the gedmatch utility- & 56.9×4=227.6cm between my parents would make them around 2nd cousins or first cousins twice removed!

11. Mary Jane Smith says:

I was adopted, and uploaded my Ancestry DNA results to the GenMAtch AYPR tool.

I am upset by the results. Partly because I don’t completely understand them, and also because they show my biological parents were related. If I’m doing the calculations correctly, they were pretty close.

I’m not sure what to do with this information. My own kids are all nearly adults now, and there are some significant health issues, as do I, and I am worried about them.

• Kitty M Cooper says:

Mary Jane I am so sorry for your painful discovery. Do read the pamphlet linked to above and perhaps join an online support group.

To slightly repeat what I said above about having closely related parents “does not mean you will have health issues and your children rate to be fine. It usually takes generations of inbreeding to cause serious problems. The issue is when you get two copies of a deleterious gene, you are stuck with it …”

If you think your health issues are genetic please discuss this with your health care provider. Have you uploaded your results to Promethease.com ??? That will list the known health issues in your DNA but of course not everything has been figured out yet

12. SFox says:

Would the GedMatch tool show if my Grandparents were related?

My father was adopted and he’s also deceased. My sister and I have both taken DNA tests from Ancestry and have a pretty clear picture of who are ancestors are…we just need to narrow down who his parents are amongst the families we show relationships to.
There are stories about a particular Uncle being very handsy (and going to jail for rape of a 14 yr old). We are wondering if it’s possible that this Uncle got his daughter pregnant resulting in our father.
Basically trying to disprove every possibility at this point.

• Kitty says:

No the Gedmatch tool would only show that for your father’s DNA.
However a one to one comparison between you and your sister would likely show higher shared DNA and more FIRs than expected for siblings.

13. Cara A says:

I’m so glad I found this and it looks like you are still answering comments. You said it takes generations of inbreeding to cause serious problems? I’m doing Ansetery DNA my results will be ready in a week.

(As far as I can see about 4 generations past my paternal grandmother…half brother and sister married had a son and a daughter, son married outside of family daughter married a cousin maybe second (I’m only doing parents in my tree) the brother and sister each had a child with thier partner and those children married each other (first cousins) Then the first cousins had a daughter and married a son the half brother and sister had much later (great uncle?) They had a daughter who was my fathers mother….and rumor has it she may have married her first or second cousin but not positive on that.)
If all of this is true and I’m pretty sure I am, I have checked birth and marrige records…will this show in my DNA results?
I have 5 children 2 autistic one of them sever as of right now nonverbal, stereotypes…(hand flapping TICS possibly seizures etc) as well as had transpostion of the great Arteries when he was born. Another child speech delay but therapists say will catch up with a year of therapy and the other child has ADHD has bad teeth and will need braces in a few years.
Hope I explained everything ok its late. Thank you for any info! If you have detailed information also please send to my email. As I don’t know how bad this is.

14. Kitty says:

Cara –
In theory if you are OK and not married to a close relative these problems in your children are not from the inbreeding a few generations back. When your results come in, you need to upload them to GEDmatch Genesis to look in more detail. Also upload to promethease.com for health results in your ancestry test.

• Cara says:

Thank you for the info Kitty! I will see how to upload my results.

Thanks for the article! It is very helpful. I have someone’s DNA test that I am helping with who was adopted and knows nothing.

We have found a couple of distinct lines and are trying to get the relationships nailed down. One match came up as a half sibling.

Comparing DNA from a half sibling and trying to piece together genealogy it appears that his parents would be 2nd cousins. Using the “are your parents related” tool does not show up any relation.

Is that possible or would the tool show the match or sure if it was?

I am willing to rethink the DNA defined relationships but don’t want to rely on this tool if it may not show more distant relations accurately.

• Kitty says:

It is barely possible that the AYPR tool would not show anything for that half sibling, but with parents of 2nd cousins I would expect to see about 50 cM there (one fourth of the average amount for 2nd cousins). So the half siblings parents are likely slightly more distanty related if related at all.

16. Marsha G. says:

This is a slightly different topic but I’ve not been able to find anywhere else to ask. My DNA and the DNA of the man I thought was my father was sent into Ancestry and we showed up with only 1689 matching cM’s across 59 segments. Is it impossible with these results that he’s my father? His sister which I believe is my aunt matched me with 1606 across 55. They had one other brother who is now deceased. Thank you for your help! Would it be possible for you to email me a response? Thanks so much!

• Kitty says:

Those numbers say his brother is your father, he is your uncle

• Marsha says:

I’m really bummed that it isn’t possible for him to be my father with those numbers, but I appreciate your quick response. Thank you.

17. Anna says:

If I am doing my math correctly my 1143.7 segments x4 are 4574.8. It’s saying 1.6 number of generations apart. Is that more likely a father/daughter or brother/sister

• Kitty M Cooper says:

Anna
Sorry I did not see this sooner…see my response to Marcos below. Probably parent/child but I will respond to you privately as well.

18. Marcos Villarreal says:

Largest segment = 91.9 cM
Total of segments > 7 cM = 767.7 cM so x4 is 3070.8 i believe. so what does this mean?

• Kitty M Cooper says:

This means your parents were siblings or possibly a parent and their child. I would need to analyze it some more to figure out which

I understand how difficult this is. there are some resources listed in my blog post

Here is an article Leah Larkin wrote about a similar situation
https://thednageek.com/gordon

19. Lydia says:

My GedMatch says parents are distantly related. My ROH is 7.2 and 701 SNPs. I can see 4th cousins that match both my father’s mother’s side and my mother’s mother’s side. What could this mean? Thank you so much!

• Kitty says:

When you multiply 7.2 by 4 you get 28.8 which can be anything from 3rd cousins to 6th cousins or even further back, check that at the calculator yourself
https://dnapainter.com/tools/sharedcmv4
The matching may mean that if you go far enough back on your father’s mother’s side you will find an ancestor that is also on you mother’s mother’s line or it could just be coincidence (depending how many of those double matches you see) …

20. Becky says:

Thank you for your time! Using GEDmatch’s AYPR tool, it did not show any relation, but then there was a link for David Pike’s analysis, which I used, but seemingly got different result from GedMatch. Pike’s result show the following:

Chr 2-ROH of 292
Chr 6-ROH of 224
Chr 6-ROH of 590
Chr 19-ROH of 215

Chr X the ROH is 17,604
Chr Y the ROH is 885

It states that total ROH is 214 and 6.786% of the reported genome, so if I times that by 4, is this 1st cousins? I thought maybe such high ROH on the X & Y chromosomes just had something to do with being male, but I tested two other males and neither showed any ROH on the X & Y.

There is a lot of other information listed that I don’t understand and Pike’s tool does not tell you if they are related or not.

• Kitty says:

Sorry I missed this question. The david Pike report is in different units, SNPs not cMs so not comparable to the tool I discuss here.

A total ROH of 6.8% is high, but not abnormal for an endogamous population or if there is pedigree collapse (e.g. grandparents who are 1st cousins). Most northern europeans I have looked at seem to run from 1-3%

21. Eugene Deschaux says:

I used the AYPR tool on the archaic DNA kits in Gedmatch.

With 4 of those kits the multiplying by four goes a bit strange because the range would then be between 4,800 cM and 12,500 cM!

The results were:
– Hinxton 3 : 1,255.6 cM, 29.1 cM largest segment
– Hinxton 2 : 1,857.7 cM, 32.2 cM largest segment
– Hinxton 5 : 2,698.3 cM, 54.1 cM largest segment
– Kennewick : 3,135.4 cM, 84.4 cM largest segment

Despite the differences in size are they all parent/child or perhaps siblings?

There is already a lot said about the Kennewick Man also known as the Ancient One, the ancestor of the Native Americans but I could not find anything mentioned about his related parents.
Since he was of above average age (around 40 years) when he died more than 8,000 years ago I guess the inbreeding did not cause any significant problems!

I initially used the AYPR tool only on the Clovis and Kennewick kits while trying to establish whether the 0.9% Mesoamerican and Andean that my father had in Myheritage is just noise or legit.
Especially since he is of Asian and European descent.

So in GedMatch I compared him with the archaic kits of Clovis and Kennewick.
When using the 0.5 cM he has :
– a HIR of 134,6 cM, 99 shared segments, largest 4,1 cM with Clovis;
– a HIR of 2,8 cM, 1 shared segment, largest 2,8 cM with Kennewick.

So it looks like he and the Clovis child do indeed have an ancient common ancestor (Asian / Beringian).

• Kitty says:

I doubt that AYPR is accurate on these ancient genomes. The multiplier is used on the cMs, not on the SNPs.

Plus comparing at such a low threshold is unlikely to produce valid results

The mesoAmerican prediction at MyHeritage is likely noise or a misinterpretation of the Asian DNA

22. Sam says:

Hello.

My question is, typically children share 50% of their genes with each parent. 50% from mum and 50% from dad.

In the case where the parents are 1st cousins, do their children share more than 50% of their genes with them? If so, how much on average do they share?

Not sure if my question makes sense, but are offsprings of first cousins parents “more related” than regular ones? Or everyone are related to their parents equally, regardless whether the parents are cousins or not.

23. Kitty M Cooper says:

They will get half of their DNA from each parent but some of the DNA from each parent will be shared with the other parent as well because they are related. However that would not show in the totals from the testing company which come just from just half their DNA, one side of the chromosome pairs, those are called HIRs (half identical regions)

On the other hane, at GEDmatch, in the comparison with either parent, they would also share some FIRs (fully identical regions), so some additional DNA. That is the DNA which shows in this AYPR tool. Places where the same DNA is inherited from each parent.

24. Peter says:

My friend is the child of first cousin parents: Does that make him more related to his parents than myself. Also does this mean he is his parents child AND their first cousin once removed ?

• Kitty says:

Unclear to me what you are asking, how are you related to those parents?

He is their child that is the relationship. These marriages were more common in past times.

25. Peter says:

A child of first cousins, is also their first cousin once removed ?

• Kitty says:

Yes the child of a first cousin is your first cousin once removed.

26. Marie says:

Bonjour Kitty, besoin d’aide pour comprendre…
Largest segment = 78.1 cM
Total of segments > 7 cM = 1028.9 cM
Est-ce plus probable un père/ fille ou un frère/sœur ?
I have adopted and want to know true.
Thank you for your time on this question.

• Marie Cécile says:

In English it is maybe more easy..
Hello Kitty, need help to understand…
Largest segment – 78.1 cM
Total of segments – 7 cM – 1028.9 cM
Is it more likely a father/daughter or a brother/sister?
I have adopted and want to know true.
Thank you for your time on this question.

27. Kitty says:

Bonjour Marie –
non ce n’est pas “un père/ fille ou un frère/sœur” – probablement un cousin premier
pardon the poor french, most likely a first cousin or a half nephew or half uncle but it depends where those numbers are from. I always use this calculator to look at the possibilities:
https://dnapainter.com/tools/sharedcmv4
and I prefer to use the numbers from GEDmatch

28. Marie Cécile says:

The results come from Gedmatch. And I thought considering the total number of cm that it could be father / daughter. Tanks for your quick responde and internet link.

• Kitty says:

If those results are from the are your parents related, then yes a parent/child. Sorry I did not see what post your question was on … but look at the charts here http://thednageek.com/gordon/

29. Peter says:

Does the offspring of 1st cousins parents, share more genes with each parent (more than 50% each), in comparison with the offspring of non related parents ?

We all share 50% of our DNA with each of our parents.

When the parents are 1st cousins, does it mean their child share more than 50% with each parent ?

• Kitty says:

Yes they will share more than 50% with each parent because some of that DNA is the same from each parent.

Since 1st cousins share around 12.5% with each other, about 3% or so of that will be passed on identically to their child

30. Nowrsky says:

What about half first cousins? How much identical dna do they pass down? Do you have any examples of that?

• Kitty says:

I do not have many examples of half first cousin but Blaine Bettinger collected those statistics and you can see the results in this online calculator: https://dnapainter.com/tools/sharedcmv4

31. monica says:

Hi, I am an adopted daughter and I know my origins. There is doubt that my maternal grandfather is my father but they are all dead. The gedmatch analysis on the rohs did not report anything. PIke’s analysis gives a different result but I can’t understand. Is there a possibility that the rohs are low in cases of closely related parents? thanks monica

• Kitty says:

Moinica, sorry I missed your comment. No there is no possibility that your maternal grandfather is your Dad if the AYPR tool finds no common segments from your parents

32. Bob says:

Sooooo….

My AYPR x 4 comes to 3505.8. I’m gonna go out on a limb here and assume my father is my grandfather. Does that sound right or could it be an uncle?

• Kitty says:

Your parents could also be siblings. Look at your matches to your mother’s mother’s side … see the charts also in the Larkin Gordon article linked to above. Hard to tell apart …

33. Kim says:

Hi kitty
I have been trying to solve a mystery. I do not know who my father is. I have done ancestry dna and after analyzing hundreds of matches I can see that there is no clear father side, every person is related in some way to my mother side. I have taken the raw dna and done the are your parents related and the answer is no. So now I am stuck as to how to proceed. My mother will not discuss the issue with me and we have been estranged for many years. I was told many lies about who my father is and supposedly given a random persons last name at my birth in the 70’s.
Are there any suggestions on how to sort through the dna matches? Are there other tools? I have used family finder as well as gedmatch but I am a novice and not familiar with the terminology.
There isn’t anyone else that I could do a dna test with for comparison.

34. Cherilyn Davis says:

Hi Kitty! I have a friend who was adopted. I encouraged her to take an Ancestry DNA. She discovered someone who shares 1219 cMs across 63 segments. We are wondering if she could possibly be a product of incest.

• Kitty says:

Cherilynn – If she has a relative who shares 1219 tha could be a number of quite close relationships, so input the number at the calculator to see the possibilities:
https://dnapainter.com/tools/sharedcmv4

This post that you put your comment on is about when you share DNA with yourself, so to speak (you got the same DNA from each parent as would happen with incest). By uploading your raw DNA results to GEDmatch, you can use their Are Your Parents Related tool to see that. I recommend all adoptees check this.

35. Louisa Martin-Kimber says:

Hi Kitty,

My mum and dad are first cousins. I have entered my kit details into the Gedmatch tool and it clearly states that my parents are “probably not related within recent generations”. What next?!

• Kitty says:

Louisa –
It seems almost statistically impossible for you not to show with related parents in that tool if your parents are really first cousins.
Are you sure you uploaded the right DNA kit to GEDmatch?
Do you have any siblings or aunts or uncles who would test? from each side of the family? That would likely clear it up. Perhaps one of your parents was adopted. Or, sorry to say, possibly your dad is not biologically your father.

• Louisa Martin-Kimber says:

Coincidentally, I have had a 372cM DNA match to someone via Ancestry. We have spoken on the phone and there is absolutely no link between our trees whatsoever apart from location ironically close to my dad’s parents.

Unfortunately my dad doesn’t want to take a DNA test and wants to let sleeping dogs lie which is a shame but understandable.

• Kitty says:

In other words, likely the father of one of their parents is your dad’s father. If they look at which side the matches you have in common with them are on, it may be easy to figure out

36. Shawn Turney says:

I’ve been helping a friend try to confirm her family rumor that her grandparents were siblings. I ran the AYPR tool and it says “No shared DNA segments. Your parents are probably not related within recent generations.” So, should this alone be proof that her father’s parents were not siblings?

• Kitty says:

Shawn –
This function only works for the child of related parents. That is because it looks for segments where you have the exact same DNA from both parents, called ROH (runs of homozygosity).
If your grandparents were related, that will not show in this tool. You would have to look at matches to each side of the family. So your friend would match people on that side of the family doubly, increasing the amount of shared DNA with those relatives.
If your friend could get the parent who is the child of those grandparents to test, that would resolve this.

• Trish says:

Hi Kitty, this is fascinating! Is it possible to tell through my DNA whether my late Father’s maternal uncle (his Mum’s uncle – brother of her Dad) was his father? Thanks!

• Kitty M Cooper says:

Yes it likely is possible but not with this tool which only would work on his DNA. You would look at the relative matching on your paternal side.

37. hippy smith says:

hi
i have been trying to research my late grandfathers birth parents who my granddad never knew. there has been a story that my grandparents might of been related in some way. in my searching i have discovered my grandfather when he was younger had the same surname as my nans grandmothers family which he changed when he got older. i have my mother and her two full brothers dna on gedmatch and i have ran all 3 using the AYPR tool and all 3 come back negative. my question is would this sort of relationship show while using this tool? many thanks and i hope this made sense..

• Kitty M Cooper says:

Hippy,
Sorry for the delay responding. This tool only works when the parents are related. Since you tested your mother and her brothers and did the AYPR tool on all of them, then their parents, your grandparents, were not closely enough related for it to show up in this tool. If they were 3rd/4th/5th cousins that might not show in the tool, anything closer would.

38. Olivia says:

How would you distinguish a 1st cousin from a half sibling, would the methods of mapping be similar? Our grandfather’s father, we speculate is also the father of my grandfather’s niece. We suspect my great grandmother had children with her daughter’s husband or the daughter’s husband’s brother.

Ran the are your parents related with result of Largest segment = 20.5 cM
Total of segments > 7 cM = 117.1 cM. Paper trail shows in addition to husband and wife that they are (SEA) half 1st cousin 1 removed along with (R family) 2nd cousin once removed, 3rd cousin once removed and 3 ways of 4th cousin once removed. And because of SEA I am my own half 2nd cousin once removed.
Does the amount seem correct with all the variables?

• Kitty says:

Yes that fits.
Multiplying the 117.1 by 4 gets you 468.4 which is on the highest end of half first cousin once removed (62-469) so undoubtedly those other relationships haved added a few cMs here and there. The problem is that after 3rd cousins the amount shared is very random.

40. Annabelle B says:

Hi Kitty, I am working on an adoption case as a DNA search angel. I identified the first set of grandparents after only after 3 hours yesterday..but couldn’t see any DNA from the 2nd parent, which has never happen to me before. So I ran the “AYPR” test for Total of segments > 7 cM = 576.0 cM. This is my first case I’ve ever dealt with parent relatedness and I have seek the guidance of the names listed at the bottom of the test (Michelle Edsel) as I couldn’t interpret the results. I won’t know for sure what the relationship between the birth parents until a few days or weeks as I’m not an expert in that field, but I’m really curious as to how do you determine if it’s an uncle/niece or a grandfather/granddaughter relationship (only the paternal grandpa was alive, there are no paternal uncles, the paternal aunt was pregnant at the same period, and there are two maternal uncles of the birth parent # 1 ‘maternal uncle A’ & ‘maternal uncle B’ of BM. A few search angels told be it’s a 2nd degree of parental relatedness…not a 1st degree (father-daughter, brother-sister)…so either grandfather/granddaughter, niece/uncle or half sister/half brother (but there are no half brother to the BM so I’ve ruled out that possibility and couldn’t even see any DNA from the ‘unrelated side to the BM’ if there was an ‘assumed full sibling’ who was in fact a half-sibling). I’ve ruled out ‘maternal uncle A’ as his granddaughter tested and was a 319 cM DNA match to the adoptee. She would have to be a half 1st cousin & 2nd cousin (so approx. share 600-800 cM) with the adoptee if ‘maternal uncle A’ was the BF of the adoptee. Here are the highest matches of the paternal grandfather’s line …do you see at all inflation… Double 2C2R (226 cM), Double 2C2R (174 cM), 3C1R (163 cM), 3C2R (158 cM), Double 3C1R (148 cM), 2C2R (140 cM), 3C (138 cM), 3C1R (137 cM on my Heritage), 2C3R (124 cM), 3C (116 cM). [There are also 177 cM, 145 cM, 131 cM, 102 cM, 101 cM, 96 cM, 95 cM, 95 cM that I can’t figure out how they match up on the paternal grandfather’s side]. Here are the matches that would relate to ‘maternal uncle B’ and here would be the ‘relationship base on my findings’ to the adoptee 2C (319 cM), 1C2R (171 cM), Double 2C2R (162 cM), Double 2C2R (109 cM) “109 cM and 162 cM are full siblings”. I have not identified the relationship between match 97 cM to the adoptee. Where would you say you see inflation on the ‘maternal uncle B’ or ‘paternal grandfather’ based on the cM I provided and the relationship I listed based on my research/archives ? Also, wouldn’t the 319 cM be (she’s the granddaughter of ‘maternal uncle A’) match to the adoptee as Double 2C if (so about 450-600 cM) “maternal uncle B” was the BF of the adoptee. Would you mind answering privately? Thanks 🙂

41. windell says:

My father and mother are 1st cousins 5 times removed. My (are your parents related )results are negative. Would that be because of the many generations apart,they share a common GGGGGgrandfather.

• kitty cooper says:

Windell –
That distant a relationship is likely not to show. Your parents may not even share any DNA. If they do share some DNA, the odds that they would both pass you that DNA are even lower.
If they share a common 5th grandad there are 6 “G”s so your relationship is a 6th cousin or half 6th …
This chart shows the probability of shared DNA anong 6th cousins as varying between companies but basically being very low
https://isogg.org/wiki/Cousin_statistics

42. Mahmood says:

My parents are Double 1st cousin.
And here my results from using the Gedmatch ‘Are your parent’s related tool’:

Largest segment = 59.9 cM
Total of segments > 7 cM = 779.9 cM

Can someone help me predict the possible relationship between my parents (genetically speaking)

• Kitty M Cooper says:

Multiply that 779 by 4 for a number to look up for a rough estimate.
https://dnapainter.com/tools/sharedcmv4

The answer is full siblings… double first cousins are expected to look like half siblings or closer in their DNA

• Mahmood says:

Why multiply the number by 4 if I may ask?

And isn’t this number too high for double 1st cousin? why are my parents more full-siblings and less half-siblings?

43. Kitty says:

The multiply by 4 is explained in the article above. as it says, “Suppose your parents share 25% of their DNA. They will pass about half of that to you, so 12.5%. However only about half of that will be the same DNA so it will show up as about 6.25% on the AYPR tool.”

yes the number is too high, could they be more closely related? Are you from an endogamous group (families that intermarried frequently)? In other words, if their parents were also related … or if their parents were identical twins rather than just siblings

• Mahmood says:

All my (4) grandparents are also 1st cousins. That it be that?

• Kitty M Cooper says:

Yes that would explain it

44. GS says:

So I’m a bit baffled. Family secret is that my paternal grandfather was the product of an aunt and nephew getting together. Both bailed on him when he was a little boy and he was raised by his maternal aunt/paternal grandmother. His birthparents both died young back during the Depression. (My grandfather is 93 years old). When I used the Are My Parents Related tool on his raw data, I was surprised to see that it came out negative. So for fun I ran my raw data. And it said that my parents were distantly related! So I ran my brother’s raw data. Said his (our) parents are not related.

Here’s my question/conundrum…both my parents have done 23andme, as well as both my paternal grandparents, and my brother and I. On 23andme, it says that my parents do not share any cMs. But on here it says the number is 7.1cMs.

Any ideas? Is it an error? Or was the family story wrong all these years, and my grandfather was fathered by someone else? And how is it that GEDmatch and 23andme do not agree about my parents?

• Kitty says:

If your parents are tested on 23andme and share no DNA there then the 7.1 on GEDmatch is just a false match. Anything less than 11cM can always be false and at 6cM it becomes even money that a match is false which is why we use 7 for matching algorithms

45. Tiffany says:

My numbers come out to the below. When I multiply by 4, it seems they would be siblings but I just want to make sure. Are my parents siblings or would it be more of a parent-child?

Largest segment = 42.4 cM
Total of segments > 7 cM = 579.3 cM

• Kitty says:

Tiffany –
Although DNApainter says the times 4 number is mosty likely siblings (74%), that is a smallish largest segment making a slightly more distant relationship probable.
The only way to figure this out for sure is to map as many of the ROH segments to the family lines. If they are all from one side, then likely they are half siblings or grandparent/grandchild. Both sides, then siblings.

46. mitzi brown stone says:

Is there any way to tell if my father’s parents were related?

• Kitty M Cooper says:

Mitzi –
If his DNA is tested then this tool will do it. Otherwise not easily. Perhaps if his cousins from each side, that are not expected to match each other, have significant shared DNA.

47. S A says:

Hello,
I had no matches on my Father’s side of my Tree. Put my DNA in “AYPR” and my large seg 131.7 and my total seg were readded to 967.42.
I had emailed help over a week ago, but no word.
Not good. Parent /Child, Parents?

• S A says:

Sorry Kitty, total Seg=853.9. When added up
907.6 x 4 = 3630.4.
Regards.

• Kitty M Cooper says:

Sorry S A, likely parent/child. Will email you privately

48. Michael Dye says:

My results indicate that my parents are probably not related in recent generations. What’s considered a recent generation? I ask because I know my 3rd gr. grandfather on my mother’s side and my 3rd gr grandmother on my father’s side were brother and sister.

• Kitty says:

So your parents are 3rd cousins? Then they are expected to share about 53cM (in the range 0-234 – histogram from DNApainter https://dnapainter.com/assets/tools/shared/histograms/3c.png )

However in order for their relatedness to show in your results, they have to have each passed you a segment from that shared part rather than the corresponding segment from the other parent. So you are likely to see about 12cM segment in the AYPR but it is completely possible that you would see 0. It is also possible that they share no DNA, about 10% of 3rd cousins have no shared DNA per the ISOGG wiki see
https://isogg.org/wiki/Cousin_statistics

I would expect that parents who are 2nd cousins or closer will always show in the AYPR tool but further cousins are not guaranteed.

• Michael Dye says:

Looking at a chart I think they would be 4th cousins. My 4th gr. grandparents would be the common ancestor.

• Michael Dye says:

What’s funny though is that my dad was born and raised in far southwest Virginia. My mom, whose ancestors as far as she knew were from Harlan Co., and Owsley Co., KY was born and raised on the Indiana/Ohio border near Cincinnati, Ohio. My dad moved to Cincinnati in the 50’s where he met my mom and they married. Neither knew they were related until I did the genealogy on them.

• Kitty says:

That is funny! As 4th cousins, about half the time they will share no DNA at all. If they do share DNA, the odds that they would each pass the same segment to you, so it would show in the AYPR tool, are vanishingly small.

49. MM says:

How do we expect other matches to show up when parents are closely related? Would the cm numbers be inflated? AYPR tool shows 261cm, which would translate to 1C range. But the closest match of this person shares 1935cm. If they are half siblings, as I suspect, then the relationship of the parents is actually uncle-niece. Possible?

• Kitty says:

Using the same logic as above, I subtact 25% from the number an AYPR person shares with another person as a rough guide. That gives 1451 so it can still be either a half sibling or an uncle-niece or grandparent-grandchild.
See https://blog.kittycooper.com/2017/09/the-25-relationship-a-first-look-at-the-data/
But if the match’s tree is known then see if you are a match to relatives on both their maternal and paternal lines. Half siblings will only be related on the one side. Is there any X match? That would be from the “uncle’s” mother and can be quite informative. But the lack of an X match is not conclusive…

• Melissa says:

Thanks for the quick response! The matches would be paternal half siblings or 1C. The 25% guideline is very helpful and exactly what I was looking for to rule out one of these possibilities.

Grandparent and “nibling” relationships can be ruled out based on ages of the matches and their mothers (and the non-AYPR match only matches on his paternal side). Thanks so much, this is very helpful!

50. Farrah McKenzie says:

Hi, My parents are related via their 5th great grandparents. When I do the tool, it says that they’re likely not closely related.

I was wondering, would they show as related if the DNA has been diluted down that many generations?

Thank you

• Farrah McKenzie says:

I used the cousin calculator because I can never keep these kinds of things straight…and they would technically be 6th cousins, if that is at all helpful.

• Kitty says:

Hi Farrah –
For this tool to find that relationship, your parents would
1) need to share some DNA
2) need to each pass along to you a segment from that shared DNA
My guess is that starting at 3rd cousins it would be hit or miss whether that shows in this tool.
Since your parents are only 6th cousins it is quite likely that they share no DNA at all and even if they shared a little it would be very unlikely for you to get the same segment from each of them. Therefore this tool will not find the relationship.

51. Colleen Lentini says:

Does the GEDMATCH “Are your parents related?” work if you don’t know who your father was and 90% of your DNA matches (Ancestry, my Heritage, 23 and Me, and FTYDNA) trace back to your mother? the remaining 10% of DNA matches are very low.

• Kitty says:

Colleen – the AYPR tool (“Are your parents related?”) just looks at your own DNA for patterns that show that you have related parents. No parental DNA is needed.
I have often seen cases where one side of the family has far fewer matches. Sometimes because that side is from a country that does not test. Sometimes due to small family sizes resulting in fewer people who could test.
Read this success story for an example of an unknown father solved in spite of very few matches: https://blog.kittycooper.com/2019/12/can-ethnicity-help-with-unknown-parentage/

52. Dear Kitty,

I got the results of two tests.

Test number 1: we don’t know this person’s father but AYPR tool shows 114.5cM, which would suggest for example 1C1R or half 1C relationship between parents (114.5*4 = 458cM).
In David’s Pike tool the result is: “The detected ROHs account for 5.432 % of the reported genome.”

Test number 2: we know that this person’s parents were 1C1R. I was expecting something around 110cM in AYPR tool. It turned out to be only 8.2cM!
In David’s Pike tool the result is: “The detected ROHs account for 2.413 % of the reported genome.”

Am I correct with suspicion, that parents of person from test number 1 were 1C1R or half 1C or something near this type of relationship? How far from this prediction the real relationship may differ?

Could it be that person from test number 2 just didn’t inherited overlaping parts of parent’s DNA and this is why the result is so small? This is very interesting why it’s only 8.2cM, while parents were 1C1R.

Which of the tools is more accurate and how to read percentage from Davis Pike’s tool?

Warm regards!

• Kitty says:

Yes your assumptions about test 1 are correct (2C is also possible – use the calculator at https://dnapainter.com/tools/sharedcmv4 to see all the possibilities)
As to test 2 that is a puzzle. DNA can be random but not usually that far off. I would suspect that the parents were not as closely related as they thought.
I do not use the Pike tool for this type of relationship prediction so cannot offer help on that.

53. Erin says:

The “Are Your Parents Related Tool” told me that my parents are probably related. Total of segments = 69.0CM. When I multiply that by 4, I get 276CM. That would make my parents cousins, right?

54. JESSICA says:

I ran the tool for my partner’s grandmother, who we don’t have a father’s identity for. Her results came back as:
Largest segment = 68.1 cM
Total of segments > 7 cM = 670.0 cM
If I’m doing this right it adds up to about 2680cM shared, which is pretty good for full siblings but on the edge of parent-child. Does that sound right?

• Kitty says:

That sounds right. How many ROH segments? Does her known mother have a brother?
You can look at the ROH segments themselves and see if any match her mother’s mother’s side. If not, then likely it was father-daughter.

• JESSICA says:

Sorry, I’m pretty new to breaking down DNA like this, haha. How do I figure out how many ROH segments?
Her mother had 2 brothers, but one was a child at the time, so that narrows it down to just the one. She does have ancestry.com matches to her mother’s mother’s side, but the overwhelming majority are her father’s side.

(Also, I just realized you and I are distant cousins via Norway! Fun fact!)

• Kitty says:

I will email you privately.
Just count up the segments listed by the AYPR tool or cut and paste the number only view into a spreadsheet

55. William says:

Both my parents have ancestors from Germany, and I have seen relatives in common pop up on both sides of my family tree, leading me to believe that my parents were cousins in the 4th-7th range. The GEDMatch tool reveals lots of green (base pairs with full match), but no segments of at least 7 cM. Since they’ve both my parents passed prior to the common availability of autosomal tests, I can’t do a direct comparison. Any ideas on how I could narrow down their shared DNA to determine their common ancestor using 23andme, GEDMatch, AncestryDNA, FamilyTreeDNA or other tools? Unfortunately, the GEDMatch tool doesn’t seem to allow for reducing the sensitivity below 7 cM, and the exact positions are only graphical presented. In eyeballing the green segments in the chart, some look to be at least 3 cMs.

• Kitty says:

I would think paper trail old fashioned genealogy is the best approach. Very few Germans have DNA tested.

As to DNA you could try uploading to MyHeritage as there are some Germans there. Can you get any 1st or 2nd cousins on each side to test?

Looking at segments visually can be misleading as cM are not one to one with the megabases see https://isogg.org/wiki/CentiMorgan#centiMorgans_vs_megabases

56. Confused says:

My parents are first cousins and I get

Largest segment = 20.9 cM
Total of segments > 7 cM = 55.4 cM

55.4 * 4 = 221.6

Is it probable that my parents are actually more distantly related? Does the largest segment tell anything useful?

• Kitty M Cooper says:

The multiply by 4 is just a guideline and DNA can vary quite widely but yes I would wonder about that result which looks more like 2nd cousins. Are either of them tested?
How are your matches to others from their common grandparents?

• Confused says:

Unfortunately I am currently the only one tested. The result above is from my ancestry data, with my 23andme data it’s even lower:

Largest segment = 21 cM
Total of segments > 7 cM = 48.5 cM

It does look like the result may be 2nd cousins or maybe 1C1R based on the dnapainter tool.
Is the 7cM cutoff used reliable? I see some smaller green stretches that aren’t being included.

> How are your matches to others from their common grandparents?

What should I be looking for in my matches?

• Kitty says:

It would be best if you combined your 2 kits, see https://blog.kittycooper.com/2019/04/make-a-combined-dna-kit-for-yourself/

In your other matches to descendants of your parents common grand parents and great grandparents how does the amount shared compare to the expected ranges? It should be on the high end or higher. Look at this chart and click on the box for the actual relationship to see the histograms
https://dnapainter.com/tools/sharedcmv4
the expectation is that they would be on the high end or above

• Confused says:

Thanks I will try to combine the kits in the future.

I don’t think the amount of shared dna distributions seem very unusual for my dna matches, not many fall in the upper range for 2nd and 3rd cousins. My community is highly endogamous with lots of cousin marriage and the results still don’t seem too high. The largest match for a third cousin is ~130 CM.

It looks like I may need to get my parents tested to figure out if there is actually something strange here.

57. chris says:

was there a change in the are u parents related recently ? and what does this specify? a daughter/father? Largest segment = 66 cM
Total of segments > 7 cM = 550.5 cM x 4 = 2202
The totals were higher a month ago so i got confused.

• Kitty says:

Chris –
This is most likely siblings. It can also be half siblings, uncle/niece, and other similar relationships (look up the number at DNApainter’s calculator). You can figure out which by analyzing the actual ROH segments, are they all from one side of the family? Then not siblings but one of the other relationships
As far as I know there was no change but log in and send a report request to ask
https://www.gedmatch.com/RTSubmit.php

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