Whether you are curious about whether you and your great-great aunt or uncle share the expected amount of DNA, or you are wondering if your mystery DNA match could fit into the great-great uncle category, you have come to the right place. A person who is your great-grand uncle, otherwise known as a great-great uncle, is a sibling of your great-grandparent.
The most recent common ancestors that you share with your great-grand aunt or uncle are your great-great grandparents. This is really amazing, since if you show up as a DNA match with your great-great uncle, then you can view it as evidence that you do descend from that set of great-great grandparents. A half-great-grand uncle or aunt is a person who is the half-sibling of your great-grandparent.
If you have a half-great-grand uncle or aunt, then the most recent common ancestor that you share with that person is one of your great-great grandparents not both. If you are interested in reading about how much DNA you should share with a great-uncle, sometimes called a grand-uncle or aunt! A grand-uncle is different than a great-grand uncle, since they are a sibling of your grandparent, instead of your great-grandparent. The expected average amount that a person could share with their great-grand uncle is about 6.
A person could share as low as cMs centimorgans and as high as about cMs with their great-grand uncle.
This general range lines up perfectly with what I have seen in my research, and with what I have experienced in my own family, although it is conceivable that there could be outliers falling slightly above or slightly below the range that I mentioned.
My adult daughter, who has graciously shared her DNA results with me for discussion on this site, has two great-grand uncles or great-great uncles, whichever you prefer on her DNA match list on two websites. They are known great-grand uncles to her, and they are related to her through different lines of my family. She shares cMs with one, and cMs with the other. On Ancestry, a great-grand uncle or great-grand aunt will likely show up in the 2nd or 3rd cousin category, as seen in the image below.
Ancestry only estimates the relationship of our DNA matches based on the amount of our shared DNA, and this means that we usually have to compare family trees and use other methods to figure out how our DNA matches are related to us. A great-grand aunt or uncle shares an amount of DNA very similar to that which we would share with a 2nd-3rd cousin.
My Heritage DNA also estimates our relationship with our matches based on similar information, but reports matches a little differently. I like the way that My Heritage sorts matches and gives estimated relationships, since it helps us understand that there is a range of possible relationships that we can have to our matches.
The first box shows the total amount of shared DNA measured in centimorgansthe second box shows the length of the longest DNA segment, and the final box shows the estimated distance to the MRCA. On the Gedmatch website, they make sure to stress that the estimated distance to the MRCA is only an estimate, and this is very similar to the estimated relationships shown by the DNA testing companies.
That means that a rule of thumb would be that a great-grand uncle would share is about These numbers should only be used as an approximate range, however, since it is possible to share slightly under or slightly over the expected range. Blaine Bettinger, a blogger who has been collecting data on shared centimorgans, reports people of this relationship distance sharing as little as 12 cMs and as much as cMs, for example.
You might have noticed that there is a big overlap in the shared DNA range for great-grand uncle or aunt. To make it easy:. I hope that this post helped you understand more about shared DNA between a great-grand uncle or aunt, and their great-grand niece or nephew. If you have any questions about something that you read here, or would like to share your experience with DNA matches to your great-grand uncles or aunts, I would love to hear from you in the comments below.
Mercedes Brons, author and genealogist, has been doing genealogy both professionally and as an amateur for more than five years. She has made it her mission to help as many people as possible understand their DNA results and learn how to build their family tree. Stay in touch on Facebook or by signing up for the e-mail list to receive the weekly newsletter. Your email address will not be published. Toggle navigation. What is a great-great uncle or aunt? How much DNA should you share with a great-grand uncle?
Scroll down to continue reading. Summary of Post. In this post, we'll discuss how much DNA someone might share with a great-great uncle or aunt, and I'll even show you two examples. Mercedes Brons.An Avuncular DNA Test is one in which the genetic material DNA of a child is compared to that of another individual to determine the likelihood that the other individual is related to the child as a biological aunt or uncle.
Because a child inherits exactly half of its genes from its biological father, and because the biological father shares on average half of his genes in common with his full sibling, the child will share on average half of its paternal genes in common with the full sibling of the biological father by inheritance. It is important to understand that, with avuncular tests, it may not be possible to achieve a conclusive result. The reason for this is that, even though they have the same parents, a full sibling of the alleged father is not genetically identical to the alleged father and may have inherited numerous genetic markers that the alleged father did not.
To increase the certainty of the results, testing the mother of the child is strongly recommended, as it allows us to identify genetic markers of the child that were inherited maternally and to eliminate them from consideration as possible paternal markers. We do not recommend performing avuncular DNA tests if the mother of the child is unavailable, due to the substantial likelihood that the results will be inconclusive.
The Y-chromosome is a DNA structure found exclusively in males and passed from a father to each of his biological sons. As a result of this pattern of inheritance, full brothers of an alleged father inherit the same Y-chromosome as the biological sons of the alleged father. Therefore, if an avuncular DNA test involving a male child and the full brother of the alleged father demonstrates that their respective Y-chromosome markers do not matchthen the alleged father can be conclusively excluded as the biological father of the child.
It only takes a minute to sign up. Jacob who shares I can narrow it down to definitely being on their father's side as they have 4 half-siblings shared mother who my Aunt's not a match with. The relationship calculator says it's most likely Half-Cousin or 1st Cousin once removed but does the X-Match mean anything?
I can't add that into the calculator. I contacted The match and we found a common ancestor that would make them 2nd cousins once removed Which is exactly what MyHeritage DNA predicted if my Aunt's father is Jacob and Sophia's great uncle.
I can't see the whole thing as it's on private because she's dealing with her own ancestry drama's. The information has raised more questions then it's answered.
But, I don't have them having a daughter called Hannah, I have them having a daughter called Anna born the same year. Which, they could be the same person, but Hannah married Anna's first cousin I know what people think about small country villages but this would be the first 1st Cousin relationship or anywhere near that I've ever seen while using ancestry, it definitely wasn't as common as people think.
The advantage of more people testing is that you can use the cM ranges better. Here, your aunt matches full siblings with different cM totals, even though they have to be the same relationship to her. You are looking for relationships where both and cM are within the range. Using the Shared CM Projectthese include:. I was able to rule out several relationships because only one of the siblings was within the cM range.
When a woman is an X match with another woman, it means nothing. It's like any other chromosome. But if a man is an X match with someone else, it means that portion of the match came from his mother. The fact that Jacob does not have an X-match with your aunt, while his sister does, increases the chance that the match is through their father.
But it does not at all rule out that the match is through their mother. Even though Sophia's X segment is large, there's a very good chance that Jacob would have no match there based on sheer luck. There's only a chance that any given segment would be inherited by a given child though it's not exact because segments break apart in unpredictable ways.
Since you already know that the match is through the siblings' father, the X-DNA is not telling you anything new. Sign up to join this community. The best answers are voted up and rise to the top.
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South Africa. Sri lanka. This test is a good option when the father is not available for testing, and the only relative available is a single sibling brother or sister of the father. DDC uses an extensive array of genetic markers to resolve more complex biological relationships like avuncular testing.
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I need help with a new test. Skip to content Facebook Twitter Instagram YouTube. Aunt-Uncle Test. Learn if a child is related to a sibling of the father. Advanced testing to reveal the truth. The DDC Guarantee:. CALL: Accreditations apply to Legal DNA tests. This will result in the potential to more accurately ascertain the relationship. This testing uses the lineage to confirm relationships.
Some DNA is passed down only from mother to child, and male to male. Our Promise to You. Fast Immediate online results.Understanding how much DNA cousins typically share is key in knowing how many common ancestors you share, and can be very helpful in understanding your family tree.
In this post, I will address the shared DNA between half-cousin relationships, focusing on half-first, half-second and half-third cousins, the closest of cousins. A cousin who is more distant than a third cousin might not share DNA with you at all, whether they are a half-cousin or a full-cousin, so typical ranges of shared DNA are less useful for those more distant relationships. The closer the cousin, the easier it is to tell whether or not your cousin is likely to be a half-first cousin based only on the amount of shared DNA.
A half-first cousin is a person with whom you share only one grandparent. Their parent is a half-sibling to one of your parents. If your grandmother or grandfather had a child with someone who was not your other grandparent, then the children of their offspring will be your half-first cousins.
The amount of DNA shared with a half-first cousin falls between cMs centimorgans. Any amount less than cMs signifies an almost certain half-first cousin relationship, since the DNA shared between two full-first cousins should fall between cMs, approximately. As you can see, there is a slight overlap in the range of DNA between full and half-first cousins. If you share between cMs with a first cousin, the only way to tell for sure whether you are full or half-first cousins would be to view close DNA matches that you have in common, or to know how much DNA your parents share.
Close relatives, as well as first and second cousins are useful as shared matches in determining full or half-first cousin relationships, since we will always share DNA with relatives at this distance, if we are truly related to them.
Avuncular DNA Tests, (Aunt/Uncle)
Some people find out that they have half-first cousins accidentally, so I have an example here of how to use shared matches to figure things out in this case:. A half-second cousin is a person with whom we share only one great-grandparent.
You will always share DNA with a half-second cousin, though it is possible to share only a small amount of DNA with half-second cousin.
You can share as little as 30 cMs or as many as cMs with a half-second cousin. As you can see, if you share over 75 cMs and less than about cMs with your second cousin, you cannot determine definitively whether you are full or half-second cousins, since this amount would fall in both ranges.
You would again have to see either how much DNA your parents share with each other, gather more data points by having more of your second cousins do a test, or use shared DNA matches to gather more information. A half-third cousin is a cousin with whom you share only one great-great grandparent.
If you have a known half-third cousin, and you share no DNA, then you cannot use only this information to decide whether or not you are truly related to each other. When you are dealing with third cousin relationships, shared matches are only generally useful in confirming a relationship, but cannot be used in determining that there is no relationship either full or half because there is always a chance that you share no DNA with a third cousin, even if you are truly related in a genealogical sense.Kendrick Lamar - DNA.
A full third cousin only shares 2 out of 16 great-great grandparents with you, and a half-third cousin only shares 1 out of 16 great-great grandparents. This means that they have thousands of DNA matches related to them in different ways, as do you, and there is always a chance that the shared matches are related to them on a different line of the family than you are, and related to you on a different line of your family than your third cousin.
I hope that this post helped you understand half-cousins and their DNA relationship to you a little better. If you have any questions about something you read here, or would just like to share your experience with half-cousins on your DNA match list, I would love to hear from you in the comments below.
Mercedes Brons, author and genealogist, has been doing genealogy both professionally and as an amateur for more than five years. She has made it her mission to help as many people as possible understand their DNA results and learn how to build their family tree.
Stay in touch on Facebook or by signing up for the e-mail list to receive the weekly newsletter. Your email address will not be published.
Toggle navigation. Scroll down to continue reading. Summary of Post. Confused about cousins? Learn about shared DNA between half-cousin relationships, focusing on half-first, half-second and half-third cousins. Mercedes Brons. Publisher Name. DNA Matches.Richard Dawkins gives a great explanation of how to calculate relatedness coefficients in The Selfish Gene :.
First identify all the common ancestors of A and B. For instance, the common ancestors of a pair of first cousins are their shared grandfather and grandmother.
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Once you have found a common ancestor, it is of course logically true that all his ancestors are common to A and B as well. However, we ignore all but the most recent common ancestors. In this sense, first cousins have only two common ancestors. Having located the common ancestor s of A and B, count the generation distance as follows.
Starting at A, climb up the family tree until you hit a common ancestor, and then climb down again to B. The total number of steps up the tree and then down again is the generation distance. Starting at A you have to climb up one generation in order to hit the common ancestor. Then to get down to B you have to descend two generations on the other side. Having found the generation distance between A and B via a particular common ancestor, calculate that part of their relatedness for which that ancestor is responsible.
But this is only part of the relatedness between A and B. If they have more than one common ancestor we have to add on the equivalent figure for each ancestor. It is usually the case that the generation distance is the same for all common ancestors of a pair of individuals. Therefore, having worked out the relatedness between A and B due to any one of the ancestors, all you have to do in practice is to multiply by the number of ancestors.
First cousins, for instance, have two common ancestors, and the generation distance via each one is 4. Welcome to the Relatedness Calculator Enter relative:. Relatedness Calculator v1. Graphs courtesy of Graphviz and Canviz.I thought it would be a great opportunity to discuss outliers and how to deal with them. Sheryl kindly agreed! Sheryl indicated that she and her mother Grace appeared to be outliers with Sally, their first cousin 1C and first cousin once removed 1C1Rrespectively.
For example, hearing someone shares cM with an expected first cousin automatically raises red flags. There are online resources and tools that allow you to look up ranges and probabilities for most genealogically relevant relationships. The 99th percentile range for 1C was cM to cM, with an average of cM:. The Shared cM Project PDF also has a histogram for the 1C relationship submissions, which is a graph that shows the distribution of these submissions I added the red arrow manually :.
The height of the bin is the number of submissions that are located within that bin or bucket. The bin, for example, has submissions. Because there are so many 1C submissions, the histogram shows a beautiful bell curve distribution, just as we would expect.
As shown by the red arrow, however, sharing of cM by suspected 1Cs Grace and Sally falls far outside the range for 1C shown by this chart. In other words, an outlier is a shared cM amount for a genealogical relationship that falls outside an expected range. Indeed, cM falls far outside the range of to cM. To use this tool, simply enter a shared cM amount in the empty field shown by the manually-added red arrow below :.
Leah used some elegant analysis to extract these probabilities, and programmer extraordinaire Jonny Perl of DNA Painter converted that information into this interactive probability tool.
As shown in the probability chart, there is a 3. But is cM for Grace and Sally really an outlier result? Or are Grace and Sally not in fact first cousins? That is the true question! However, it is only an outlier if Grace and Sally are in fact first cousins. If they are actually another relationship for which cM falls within the range, then the result is not an outlier.
It assumes an outcome and clouds judgment, potentially leading one to ignore or devalue contradictory evidence. When a shared cM amount is very low or very high, a red flag is raised and we must do our best to resolve that red flag using a combination of documentary research and additional DNA testing. Anything else is confirmation bias. Indeed, even if there is a VERY well-documented tree showing that Grace and Sally are first cousins, the fact that they share an unexpected amount of DNA as demonstrated by a scientifically solid analysis means that there is potentially a conflict between the tree and the DNA.
It is our job as genealogists — professional problem solvers — to resolve this conflict with additional evidence. How do we resolve the conflict with additional evidence? We go out and identify or generate that additional evidence. We generate a hypothesis by taking the information we have so far, scant as it may be, and formulate some educated guesses to explain the information.
If we disprove a hypothesis we can discard it. We could conceivably come up with other hypotheses, although these are by far the two most likely scenarios. For example, a possible hypothesis is that this data was falsely placed by aliens to achieve some otherworldly-goal, but generally speaking we are going to ignore that hypothesis for every analysis!
How do we test a hypothesis? Firstwe must reexamine the documentary trail. Is there any suggestion or evidence in the documents that Grace and Sally are not 1C?