One of the most common questions I receive, especially in light of the interest in ethnicity testing, is how much of an ancestor’s DNA someone “should” share.
The chart above shows how much of a particular generation of ancestors’ DNA you would inherit if each generation between you and that ancestor inherited exactly 50% of that ancestor’s DNA from their parent. This means, on the average, you will carry less than 1% of each of your 5 times great-grandparents DNA, shown in generation 7, in total. You’ll carry about 1.56% of each of your 4 times great-grandparents, your 6th generation ancestors, and so forth.
As you can see, if you’re looking for a Native American ancestor, for example, who is 7 generations back in your tree, if you carry the average amount of DNA from that ancestor, it will be less than 1% which will be under the noise threshold for detection – and that’s assuming they were 100% Native at that time.
Everyone inherits 50% of their DNA from their parents, but not everyone inherits half of each of their ancestors’ DNA from a parent. Sometimes, the child will inherit all of a segment of DNA from an ancestor, and in other cases, the child will inherit none. In some cases, they will inherit half or a portion of the DNA from an ancestor. In reality, the DNA segments are very seldom divided exactly in half, but all we can deal with are averages when discussing how much DNA you “should” receive from an ancestor, based on where they are in your tree.
The generational relationship chart above represents the average that you will inherit from each of those ancestors. Of course, few people are actually average, and you may not be either. In other words, your ancestor’s DNA may not be detectible at 5, 6 or 7 generations, because it was lost in generations between them and you, while another ancestor’s DNA is still present in detectable amounts at 8 or 9 generations.
How Does Inheritance of Ancestral Segments Actually Work?
For you to inherit a particular segment from one GGGGG-grandparent, the inheritance might look something like this. “You” are at the bottom of the tree. You can click on any graphic to enlarge.
In the above example, you inherited one-tenth of the segment from your GGGGG-grandparent which was one-third of the DNA that your parent carried in that segment from that ancestor.
A second example is every bit as likely, shown below.
In this second scenario, you inherited nothing of that segment from your GGGGG-grandparent.
A third scenario is also a possibility.
In this third scenario, you inherited all of the DNA from that ancestor as your parent.
Now, think of these three scenarios as three different siblings inheriting from the same parent, and you’ll understand why siblings carry different amounts of DNA from their ancestors.
Of course, the child can only inherit what the parent has inherited from that ancestor, and if that particular segment was gone in the parent’s generation, or generations before the parent, the child certainly can’t inherit the segment. There is no such thing as “skipping generations.”
In this fourth scenario, the parent didn’t receive any of the segment from the GGGGG-grandparent, but maybe their brother or sister did, which is why you want to test aunts and uncles. Testing everyone in your family available from the oldest generation is absolutely critical.
This, of course, is exactly why we test as many relatives as we can. Everyone inherits different amounts of segments of DNA from our common ancestors. This is also why we map our matching segments to those ancestors by triangulating with cousins – to identify which pieces of our DNA came from which ancestor.
Seeing examples of how inheritance works helps us understand that there is no “one answer” to the question we want to know about each ancestor – “How much of you is in me?” The answer is, “it depends” and the actual amount would be different for every ancestor except your parents, where the answer is always 50%.
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Thank you
My question is , does FTDNA use a tringulation method to give the matches indicated ( be it ydna or mtdna) and if not, why not, and what method do they use?
kind regards
Triangulation, by definition, has to include the identification of ancestors. So by that definition, no. However, when you connect your DNA to your tree and the DNA of your relatives to them in your tree, then the matches that they designate as paternal or maternal are indeed, utilizing the matching DNA segments of both you and those other people – so in this way, yes.
Thanks
So , I have connected my tree . This gave me 2 x 4th cousin matches on my maternal side ( respec. 107cm ( daughter ) and 177cm ( mother )) and we match on my tree between the years 1780 to 1800. Since this is correct via registry records is it not too far back in time for a score of over 100cm segment matching?
It seems that the division of ones ancestors for oneself must be not exacting in percentage.
warm regards
That is exactly right.
My maternal grandmother tested with Ancestry last year, and I was very surprised at how low our match was (1348 cM, according to Gedmatch). This showed me that the inheritance of DNA can be haphazard indeed beyond the parent/child relationship. I estimate that I share around 19% of my DNA with her. She has a parent/child match to my dad, and I have a likewise match to him.
This article should be a lesson and reminder for everyone to make an effort to atDNA test your elders, including grandparents, parents, and aunts and uncles. Glancing at all the charts, you can see how testing an elder can gain you additional generations of matches. I will be forever grateful that my 83 year old uncle agreed to test, and have me administer his results. My uncle’s DNA matches at Ancestry have been a significant factor in breaking down walls in our shared lineages.
Thank you for the explanation of how DNA is/is not passed on through succeeding generations. I had a male 1st Cousin, Once removed (one of two brothers, the last males in the line of my Grandfather and their Great Grandfather) tested through FTDNA. I had to drop the search criteria to 300 SNPs / 3 cMs to find any matching DNA between us. He actually had more DNA in common with my 2nd Cousins (his 2nd Cousins, once removed) who had also tested at FTDNA, than he did with me. I guess I just got more of my Mother’s DNA, than I did my Dad’s. Eileen Miller
On Tue, Jun 27, 2017 at 12:15 PM, DNAeXplained – Genetic Genealogy wrote:
> Roberta Estes posted: “One of the most common questions I receive, > especially in light of the interest in ethnicity testing, is how much of an > ancestor’s DNA someone “should” share. The chart above shows how much of a > particular generation of ancestors’ DNA you would inh” >
Thanks for the interesting article. I was surprised to learn that I have about 1% of East African according to My Origins 2.0. My Origins 1.0 reported 3% North African DNA while My Origins 2.0 didn’t report any North African (Middle Eastern) or Sephardic DNA.
Gedmatch confirmed that I have 1-2% of East African DNA and 3-4% of North African JEWISH DNA. In fact, the Gedmatch admixture utilities overemphasized the ancient Sephardic ancestry and assumed in some cases I was an Italian Jew. I’m curious about which of my long-lost relatives might be carrying those genes from SW Europe and Africa. My known ancestry is Eastern European Jewish.
Karen Smith
I have 5 first cousins grand parents so how does that contribute to my DNA?
Your DNA would still be divided in half, but you could be expected to retain more of the original ancestor’s DNA than otherwise. It makes it more complex, that’s for sure – but on the other hand, you also retain more of the original ancestors because you have more than one line to them.
There is a slightly different perspective between total DNA and individual segments of DNA. Each segment is rarely divided close to half way – each segment can be divided into anything from 0/100 to 100/0, and wild swings are often seen. The total amount of DNA from an Ancestor (the sum of all segments) will tend much more toward 50/50, or somewhat closer to that. And the deviation from the nominal can grow in either direction. For instance if you got 23% of your total DNA from your paternal grandfather; you had to get 27% from your paternal grandmother.
Wonderful post Roberta!
For those of you interested in how 4 generations of inheritance look in practice, I did a chart for a group of my Norwegian cousins who have 4 generations tested. Interestingly a whole chromosome stayed intact all the way to a great granddaughter (chr 22) and another was almost all there (chr 6)
http://blog.kittycooper.com/2014/05/etne-endogamy-and-four-generations-of-dna-for-my-norwegian-descended-cousins/
Plus Angie Bush also has 4 generations tested, again 2 chromosomes remained intact see
http://blog.kittycooper.com/2014/09/using-the-chromosome-mapper-to-make-a-four-generation-inheritance-picture/
Thanks for these great references, Kitty.
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Hi, I am a male who was born in Egypt to Egyptian parents, but my dad tells me he probably had an ancestor from somewhere around Turkey, he believes it could be Armenia. She/he may have immigrated to Egypt during the Armenian genocide in the early 1900’s. My mom also tells me she may have a Turkish ancestor. I wouldn’t be surprised if that is true. My grandmother on my dad’s side was so fair you would never tell she was Egyptian (she was born in Egypt though and her parents were also born in Egypt). Long story short, I’m dying to find out where the hell my ancestors came from (as even myself, I am too fair-skinned compared to the average Egyptian). I bought a 23andme kit from Amazon, then bought the LivingDNA kit when I found out it can show you the maternal and paternal lineage. I intended to return the 23andme kit. Now I read that LivingDNA works best if you have mostly British ancestry (which I definitely don’t). So which test do you recommend? Thanks!
LivingDNA would be my last choice.
Hmm.. I was excited by the fact that LivingDNA has “Armenian” listed as one of the regions tested. None of the other kits has that.
Generally their eesults are not comparing well, but I have not heard reports from anyone from Armenia.
Thanks. Would you recommend AncestryDNA over 23andme in my case?
I did ancestry DNA test it came back 75% great britton where as my parents one has trace amount of great britton the other 23% so how can I be 75% idk? Sounds like it skipped a generation?
This is why ethnicity estimates are just that, estimates. Cocktail party conversation only.
Can recessive genes in parents be passed on and dominant in their children?
https://en.wikipedia.org/wiki/Dominance_(genetics)
Quick question. My dad’s parents were 100% Scandinavian (Sweden and Denmark) for many generations back as far as I could trace to , so my dad should be 100% Scandinavian. But when I tested i got 29% Scandinavian. Is that because I inherited more DNA from my mom?
My dad also was 100 Percent Scandinavian (Norwegian/Danish) as far back as we can trace (about 8 generations) but I show only 6 percent. Sadly he passed before DNA tests were common but that seems such a low percentage.
I have noticed that there is generally a lot of UK and German heritage in Danish Ancestry. Especially coming from Jylland, with England to the west and Germany to the south. Southern Jylland used to be part of Schleswig. some of my ancestry is from Augustenborg.
I are recently had a DNA test done through My Heritage and the OTHER 15.5% which in included 13 other area of Europe (Baltic States) and North Africa (Morocco to Egypt) and the Middle East (Iraq, Iran, Syria), also included Nigeria and Cameroon. I don’t know what the percentage is for those two countries but it must be 1-2%. Would that slight amount show up in my ancestors back to the 7th. generation and my siblings?
Ethnicity tests are only estimates.
Hi Roberta,
Do you know what 1/8 cherokee would show up as on the ancestry DNA test?
Thank you; your blog is very helpful…
Today’s article has a chart you’ll find useful I think.
Great Article. Explains many things. I have a 4th cousin (shared GGGfather) I found through a DNA match, and once I contacted him I filled in the branch of the tree I had not yet completed and confirmed our relation. What makes me curious, is his son recently did a DNA test, and my connection was stronger to the son than him. (Son: 71.4 cM 2 matching segments largest 41.5 Father: 69.6cM 2 matching segments, largest 43) I would have expected it to be less. Is there a ‘margin of error’ when we are talking about a sample this many generations?
You may be identical by chance at the beginning or end of the segments.
In my family there are three sisters married to three brothers. So my Mother and her two sisters and my Father and his two brothers. Each couple have had 3 children. What I find strange is not one of us cousins look alike we all look so different. Surely our DNA should be pretty close? Would this be due to each of us cousins inheriting different percentages from the various generation levels? All the cousins have had kids, would our kids be considered first cousins or second cousins?
DNA recombined in various unpredictable ways. You relationships would be both.
My Parents are deceased , as well as all my aunts and 1 uncle is alive. all I have is one brother, and sister both are estranged for one reason or another so getting them to co-operate/ participate/share any information is next to impossible. Where do I go from here/ what are my options if any?
Thanks
Test yourself and if you can find someone else, test them too. You may match people you had no idea that tested. Be sure you’re in all of the databases. Here’s an article that discussed different testing and transfer strategies. https://dna-explained.com/2017/04/11/autosomal-dna-transfers-which-companies-accept-which-tests/
Thank you!!! So very helpful for is that have brick heads when it comes to understanding DNA.
is this right? I am 99% scandinavian/Nordic and 1% native american. I heard that my great grandfather was 50% native american. Is this right ? or was he only 25% native american? Is there any way i can find the tribe my ancesters belonged to? I think this i a strange combination of 99% scand/nordic and 1% Native A. but one of my siblings are tested and it turns out to be correct. I just wish we were able to find the Native /indiginous also called “Same people” in Scandinavia on the test ,but they do not come up as anything else….Do yuou have any advice on how i can find my Same/native dna? I know i have Sameblood gfrom both parents.
Yes, look at the Native link st the top of the blog for resources and directions.
Ann -K, have you ever done genealogy? That has been such an interesting thing, I found some really nice surprises, and one that was kind of a bummer – not having all these Indian (my Lakota friends identify as Indian, so I use that word as well) relatives tucked away somewhere. It seems to be a family lore thing, especially in Oklahoma. But maybe you will find your Great-Grandfather that way. Do you have living relatives who might know?
And Roberta, this is all so fascinating, thank you so much! I am sending this Blog to my Dad, he will really enjoy it as well, thank you so much for spending so much time on this and for sharing it with us.
This is an interesting analysis to tell people to leave a record of their life particularly in the area of physical and mental spheres for the future generation which can know their ancestry so as to take care of their future life.
I have second great grandparents that were immigrants from The Azores. Two second cousins have DNA tested with results of 8 and 15% Iberian Peninsula…. I have zero. I have had my DNA results from both Ancestry and My Heritage, and zero Iberian Peninsula. Two of my three daughters have trace amts of Iberian Peninsula in their DNA results. How is it possible I have zero?
Ethnicity is only as estimate. https://dna-explained.com/2018/12/28/ethnicity-is-just-an-estimate-yes-really/
Ethnicity is just an estimate. https://dna-explained.com/2018/12/28/ethnicity-is-just-an-estimate-yes-really/
Thank you so much for your informative article. It helped me considerably. But may I offer a possible correction? At the end of the paragraph below the first chart you wrote “You’ll carry about 1.56% of each of your 6 times great…etc.” Shouldn’t this read “4 times great…?
Yes, you’re right. It should read 6th ancestor of 4th great. Thank you.
can my british heritage dna”ethnicity” dissapear even if it is 6- 8 geberations back, because my 6-8 great grandfather was british, and i don’t show any british ancestry
Yes, it can.
and if i am a male and he is on my mothers’s side can i still say i am related to him, because i have his names although it has somehow been passed down to maternal lines
No, you need to gather various forms of evidence.
I had my DNA done by Ancestry and my mother’s father was supposed to be Italian and although I can trace his parents back to Verona, Italy, no Italian is showing up in my DNA. To me, this would me he is either not my grandfather or adopted. Please comment.
NO, NO, NO – 1000 times NO. Ethnicity estimates within continents are NEVER reliable enough to cause you to doubt parentage.
How can this possibly be? Is it because of border lines being moved so much over time?
How normal is it to not inherit DNA from a 4th great grandparent (no DNA matches back to 5th great grandparents, despite many descendants of the couple)? It still boggles my mind that I have DNA connections back to 7th great grandparents on certain sides and nothing past 4th great grandparents on others.
It could happen. Perhaps the right people haven’t tested. Or perhaps there is an issue with the genealogy. Track the segments back in time.
I just got my DNA back and I noticed 1 percent of one ethnicity. If I have 1 percent of that ethnicity will it show up in either my mother or father? Is is something I could have inherited from a ancester that wouldn’t show up in my mother or father?
Ethnicity is just an estimate. If it’s real, one of your should have it too.
Hi, I was donor conceived. My mom’s family is mostly Irish with a little Czechoslovakian in there somewhere. I’ve been told that my donor’s mother is/was French and his father is/was Latino. I have two siblings. One of them has straight jet black hair, brown eyes, and dark olive skin. My fraternal twin has dark olive skin, but brown hair and hazel eyes like me. And I have fair skin, hazel eyes, and wavy brown hair. Is this an indication of my sister having more of my paternal grandfather in her than me and my brother? Or did his genes just choose to express themselves more in her?
Traits are complex and often involved multiple genetic locations. It’s all about how millions of different genetic locations happen to combine.
I have 6 single male European ancestors and my DNA ethnicity is 15% European. Does
this equate? Does this make sense?
It depends how far back they are in your tree.
Why don’t you explain that this chart is based on perfect dilution from generation to generation, but the actual percentages must vary according to chance? For example, there is a certain percentage chance you inherited no DNA from one or more of your 3ggrandfathers, as you must know. Thanks.
Hi Harvey. I have explained that over and over. This is the average. It’s very unlikely that we don’t inherit anything from our 3ggf but statistically, it’s possible.
Thank you for this, it’s been extremely helpful in clarifying some confusing info revealed in my dna test. I’m realizing how much of dna testing is still guess work, but also why I’m SO different from my bio siblings.
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Thank you for your article. If two people who are romantically involved discover that they have a DNA match, (3rd/4th, 73cm or 4th/6th generations, 42cm), would this affect the health of future children in any way?
That’s a medical question and I’m not qualified to offer an opinion. I would suggest that they contact a genetic counselor and have pre-testing done.
What are the statistical odds (approximately) that a child could inherit almost all of one parents ethnicity. For example, if dad was 40% African, mom tests as 0% African (and her results make perfect sense based on where she was born – Siberia… With ethnicities typical for Russia… Baltic, we Eastern European, etc. With a little Asian and a dab of Immunity)…. Anyway if dad was 40% African, is it almost impossible the child would be 35% African? FYI, the child’s father is actually unknown yet… So giving stats won’t risk hurting someone who defy odds and this is their ethnicity and I realize anything is possible. Thank you so much!!
It’s not impossible. And given the uncertainty about the father it’s speculation at this point because we don’t know the father’s percentages. Plus the inherent uncertainly about ethnicity as a whole.