Is birthmother sharing only 1549 centimorgans possible?

6

I'm adopted. I found my birthmother over 20 years ago. After a DNA test it shows we share 1549 centimorgans over 51 DNA segments.

Is it possible that the DNA test had inaccurate results while processing or the DNA was tainted somehow?

Angela G

Posted 2018-06-20T06:01:36.467

Reputation: 61

As of today, my "birth mother" is not communicating with me at all. I've sent messages to all my close relative matches on Ancestry but no one has responded. I'm starting to believe that the DNA test results are correct. I've ordered another DNA test through Family Tree DNA just to try and make further connections. We'll see also if those results are different than ancestry. – Angela G – 2018-06-25T16:40:56.933

If the test is correct, then I'd say she is most likely an aunt and you are her sister or brother's child. – lkessler – 2018-07-09T22:59:12.437

Answers

2

Entering your shared 1549 Centimorgans into the Shared cM Project tool at DNA Painter suggests a number of possible relationships.

None of them indicate that this lady is your birthmother, but she is certainly at least a close relative.

One possibility may be that you are actually her granddaughter. That possibility would rely on her being old enough to have a child who was old enough to be your mother or father.

PolyGeo

Posted 2018-06-20T06:01:36.467

Reputation: 10 741

She is the one listed on my adoption papers and there are only 22 years between us. I was adopted as an infant, so I never left the hospital with anyone other than my adoptive parents. – Angela G – 2018-06-20T13:04:18.130

That seems like good evidence for scuttling my best theory. – PolyGeo – 2018-06-20T13:10:45.263

I know. I'm completely perplexed. Unless there was some grand Ocean's 11 style switcheroo and cover-up. – Angela G – 2018-06-20T13:30:10.213

1@AngelaG Has anyone else in your birth mother's family tested? People do get the tests mixed up sometimes if they are testing multiple family members at once. – Jan Murphy – 2018-06-20T20:55:56.310

Jan, no, nobody else has tested. – Angela G – 2018-06-21T00:39:53.250

2

If you know for certain that this is your birth mother, then the results are incorrect.

DNA companies have been known to make mistakes, the data might not have got loaded correctly, etc.

I'd recommend you contact the DNA company(ies) involved and get them to recheck your sample and to ensure everything has been processed correctly.

lkessler

Posted 2018-06-20T06:01:36.467

Reputation: 16 148

So what other measures would you suggest for them to get more information? Could they take another autosomal test with a different company to get a 'second opinion'? Taking an mtDNA test to see if the results are compatible with a mother-child pairing seems like overkill. – Jan Murphy – 2018-06-21T23:30:39.507

@Jan. If she knows for certain that it is her birth mother, which she says she does, then there's no reason for them to take another test. My recommendation to contact the DNA company is so that they can get the company to fix their incorrect results. – lkessler – 2018-06-22T01:10:08.777

1

@JanMurphy An mtDNA test would definitely be overkill, and, at most, it would only show that the two are matrilineally related. With FTDNA's mtDNA test, a match can have a most recent common ancestor between 5 and 52 generations back ( https://www.familytreedna.com/learn/mtdna-testing/tell-closeness-relationship/ ).

– Leah Worster – 2018-06-24T16:21:30.297

1

Looks like she is your aunt or half-sister. Perhaps she is protecting someone. Does she have a younger sister?

Did you see her take the test? Could her child or sister have provided the sample instead of her?

Rusty Erpenbeck

Posted 2018-06-20T06:01:36.467

Reputation: 3 576

1

My 2 cents: she is your half sister or your aunt i.e. one of her siblings is your biological parent. Only 22 years older -- unlikely to be your grandma.

My own half sister shares a little over 1800 cms with me.

Kelli

Posted 2018-06-20T06:01:36.467

Reputation: 51