Errors of this magnitude are possible but very very rare.
I'm sorry I don't have the documentation but there was discussion on at least one of the lists/groups for genetic genealogy about a case where an AncestryDNA customer was told that someone matched her as a parent. Huge surprise. Turned out to be a bizarre error and the two people weren't even ...
The adoptee is very likely your niece, specifically the half-sibling of the niece you have also tested. The relationship could be diagrammed as follows:
The X-DNA is key to determining this relationship. A useful article to help understand X-DNA matches is X Chromosome Recombination's Impact on DNA Genealogy.
You know that the adoptee is a nearly 100% half ...
The result should be reliable in that it shows a close relationship. As shown on the Autosomal DNA statistics page on the ISOGG Wiki, the relationship is almost certainly one of these:
one of you is half-sibling of the other
one of you is aunt or uncle of the other
one of you is grandparent of the other
one of you is double-first-cousin of the other
Just a note that you should not automatically jump to the conclusion that you and your probably-half-sibling must share a father instead of a mother; young unmarried pregnant women were often pressured to give away their babies and never speak of it again. Your DNA results should be able to show whether you two specifically share an X chromosome match or ...
The Shared cM Project 3.0 tool v4 suggests these possible relationships for 2,063 centimorgans:
I think the age difference of just a few years between you and this person lets us rule out grandparent to grandchild and great aunt/uncle to great niece/nephew.
2,063 is considered a little low for full siblings because they normally fall in the 2,209–3,384 ...
A possible explanation for these results is that you have more than one relationship – maybe you are half-siblings and also share a more distant relationship on your mother's side. For example, the man may be your half-brother because you share a father, and also be a second or third cousin via his mother.
Just to diagram this possible scenario to give you ...
Based on the information provided I belive are only one of two scenarios are possible.
You share a grandparent on your mothers maternal side.
You are half brother's and sisters with the same mother; not your fathers side.
You can reference the ISOGG Autosomal DNA Comparison Chart.
But a more practical example of a similar situation is my grandfather.
There is no such thing as a cut-off, just a range of probabilities.
The Shared CM project tool shows that half-sibling is one possibility with that amount of shared DNA, but there are others that are equally possible. If you've done a lot of research on the family, the WATO tool can help you model the possibilities and assess which is most probable.
According to Blaine Bettinger's Shared cm Project - Version 3.0:
Cluster #2 is: Half Sibling, Aunt/Uncle/Niece/Nephew and Grandparent/Grandchild
Cluster #3 is: 1st Cousin, Half Aunt/Uncle/Niece/Nephew, Great-Grandparent/Great-Grandchild and Great-Aunt/Uncle/Niece/Nephew
The 99th percentile range of Cluster #2 is 1294 cM to 2230 cM with an expected value ...
I had a similar situation with DNA suggesting a half sibling. When looking at shared matches, my half sibling and I shared the same relatives On both of my father’s parents side. No doubt he is my father’s son. I have met my half sibling and, after the initial shock, it has been a blessing for me.
Adding another answer in order to address two new additions to the original question, each of which could be questions on their own.
1) The Biogene test is not the same test as we use for genetic genealogy. It's a paternity test, so to speak. It looks at a few important markers and uses them to determine very close relationships.
Bio-Gene DNA ...
DNA is not something one can do easy-peasy relationship labels with, especially when it comes to conflicting stories. The Match List will give you the 'norm' label for that DNA range. And it is a range! Each relationship has a minimum and a maximum DNA count for CM that can fit for that relationship. However, if you add in endogamy (i.e. cousins marrying)...
According to the Shared cM Project, a woman with 1053 shared cM could be your:
First cousin (553-1225)
Half aunt/niece (500-1446)
Great aunt/niece (251-2108)
I have left out some relationships, such as great-grandchild, which seem unlikely.
Data from the DNA Detectives predicts the same relationships, giving all a range of 575-1330 ...
You can make a reasonable assessment of whether your match could be on your maternal side by consulting the Shared cM Project tool (link here). If you plug in 475 for the number of cM you match, you'll see that the possible relationships falls into one of three different level groups. The relationships within a group have equivalent amounts of relatedness. ...
DNAPainter suggests several possible relationships for 1782cm shared DNA.
I suspect that some of them you can rule out immediately (grandparent, for example).
But yes, half-sibling is one of the possibilities.
Assuming that this suspected half sibling is of the same generation as you (which his age suggests), and because the shared cM for each of you and your full siblings with him falls "within" the range (1317 – 2312, mean 1783) suggested by The Shared cM Project 3.0 tool v4 for half siblings, I think it likely that he is a half sibling to you.
DNA Painter thinks that the probability of 1449 cM being a half-uncle/aunt relationship is only 5.5%. It's much more likely that he's her full uncle, meaning the following diagram accounts for all of the numbers you've given:
| | |
D E F---G
Here, D is you, E is your male DNA match, and H is your ...
There's no contradiction.
It's 3.3 times more likely that you and your sister are half-siblings than not.
Which is not as strong support as it would be if (for example) it was 100 times more likely that you and your sister are half-siblings than not.
If you want to investigate your degree of relatedness further, you could both do autosomal DNA tests with (...
If your brother is the child of your grandfather and your aunt then your niece will not have any DNA matches to your mother's family. If you and your niece have close shared matches to your mother's family that would disprove your theory. Not having close shared matches to your mother's family would not prove your theory it would just indicate that you and ...
OK, so am I understanding it correctly that you have the following set of relationships:
?1 --- A --- B
C --- D E --- ?2
where F is you, and G is your cousin?
The easiest explanation for a match of 1760 cM between F and G is if ?1 = B, that is, your dad (B) is actually your aunt's (E's) full sibling, ...
If I understand your correctly, "father K" is your biological father and not the biological father of your B, J and M half-siblings.
It is possible that your biological relation to your half-siblings is more complicated and unexpected than just half-sibling. There are two ways an unusually high amount of your DNA matches DNA from father B or J or M and ...
DNA Matches of 1,591cM and 1,773cM indicate half siblings as being a possible relationship.
On the strength of those matches the two people could also have one of these relationships to the person tested:
but perhaps these can be ruled out on what you know of your family's generations.
As half siblings on your mother's side, you and your half sibling will share approximately half of your mother's chromosomes and none of your father's (assuming your sibling is not related to him in some other way).
What that means is that each match that you have on your mother's side has a 1/2 chance of also being a match of your half sibling. For 23 ...
I think you have two questions in one.
First, you need to learn the way half-siblings match work. If the shared DNA strongly shows a possible positive result, there you have the response.
Check this response: Distinguishing half-sibling, uncle or half nephew using Ancestry DNA?
If there's no match, but the results are still confusing, you can point to the ...
The Shared cM Project 3.0 tool v4 for 1,864cm suggests that by far the most likely options are:
Grandparent / Grandchild
Aunt / Uncle / Niece / Nephew
with near zero probability for:
Great-Aunt / Great-Uncle / Great-Niece / Great-Nephew
If you are confident that your sister is of the same generation as you, then I think the above ...
Half-sibling is one of the possibilities. If you go to The Shared cM Project 3.0 tool v4, you 'll see that the full list of options include:
Grandparent Aunt / Uncle Half Sibling Niece / Nephew Grandchild
You may be able to eliminate some of these if you know the age difference between the two matches.
You can plug your shared cM number into the DNA Painter tool here:
The tool indicates that 1366 cM is beyond the 99th percentile range for 1st cousins. The only same-generation relationship candidate is half-siblings.
I would consider Blaine Bettinger a reliable source on this.
I think a higher number is more likely in general through cousin marriages.
To get a much lower number it requires some “bad” luck on the randomness of DNA but it usually is a couple generations.
What I’d suggest is that you look for other matches and how they related to everyone. The more data points you have, the clearer it becomes which hypothesis is ...
A female sharing 1053 cM with you could be your:
First Cousin: The range is 553-1225 cM
Great-Aunt: The range is 251-2108 cM
Half-Aunt or Half-Niece: The range is 500-1446 cM
Great-grandmother: The range is 464-1486 cM
Double first cousin once removed: Expected to share around 850 cM
As your mother isn't related to the woman, she could not be your great-...
Here's a link to a visual representation of how someone sharing 1053 cM with you could be related: Shared cM Project tool for 1053 cM
The potential relationships, and how that connects her to you:
First Cousin: your dad would have an unknown full sibling, not half. (You and she share too much DNA to be half-first cousins.)
Half-Aunt: she would be an ...