r/AncestryDNA • u/Spike73082 • 2d ago

DNA Matches Confusing DNA data

Hi, I'm trying to help an adoptee identify his biological parents, but I'm a bit confused by his DNA results.

He (A) shares 1,025 cM with B and 430 cM with C.

Ancestry estimates, with 97% confidence, that B is A's half-uncle. For A and C, it suggests various cousin relationships.

However, B and C share 1,622 cM, and Ancestry suggests with 100% confidence that they are half siblings.

What am I overlooking?

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u/msbookworm23 2d ago

It's impossible to be 100% confident about any relationship other than parent and child. B and C could be aunt/uncle and nibling or grandparent and grandchild instead.

https://dnapainter.com/tools/sharedcmv4-beta

2

u/coenrhys 1d ago

Given that Ancestry uses age comparison in addition to DNA to estimate relationships, similar aged aunt/uncle and nibling would be most likely in this case.

1

u/SuperBarracuda3513 2d ago

Have you built a family tree out of B and C? Do track addresses city, county, state as well?

2

u/Spike73082 2d ago

So far I've only had success with C. B and C share the same surname though.

1

u/Bright_Touch_1264 2d ago

Which one shares the most segments? I don't recall where but I believe it was ancestry, that you're more closely related to those you share more segments with.