Questions tagged [autosomal-dna]

For questions about autosomal DNA testing for genealogical purposes. Autosomal DNA is the majority of the DNA in our chromosomes, and is passed by both mother and father to child. This includes tests provided by AncestryDNA, 23andMe, and FamilyTreeDNA's FamilyFinder.

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Ancestry.com "Common Ancestor" algorithm

Ancestry.com has a feature where it will use all available trees to find a common ancestor for a DNA match. I believe that it looks for overlaps in trees. It has done a good job for many of my matches....
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How to map BAM file from hg38 to hg19 for GEDmatch kit creation?

I have a Whole Genome Sequence (WGS) test from Nebula which results in a hg38 BAM file. I'd like to generate a kit on GEDmatch.com which requires hg19 BAM together with the WGS Extract tool suite to ...
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1st – 2nd Cousin 395 cM | 6% shared DNA Father's side [duplicate]

I've connected with a cousin on ancestry.com and 23andme and dna doesn't lie he is my cousin. however we cannot find out who our common ancestor is. 1st – 2nd Cousin 395 cM | 6% shared DNA Father's ...
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Thought godmother wasn’t related, but she’s a MATCH?

Close Family – 1st Cousin 24% sharedd DNA: 1,677 cM across 42 segments. I was always under the impression that my godmother was not my relative, but, much to my surprise, the above results came back ...
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Distinguishing niece from sister using shared percentage DNA [duplicate]

On Ancestry who I thought was my niece my oldest sisters child shared 49% -56% dna how is that possible ? I also have a first cousin who shares 26% yet his sister only shares 6% why is that
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1st cousin or half-sibling

Here is the background: I've matched with a person on 23andMe. We have 1217 cM shared and 35 segments. The longest segment is 114.20 (and there's also a 108.44 cM segment, and several medium lengths). ...
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Using DNA to distinguish product of NPE from secret adoptee

I'm helping a friend J work out her paternal ancestry. She is pretty certain of the identity of her biological father. His own father was supposedly wholly Polish while his mother was English/Scottish....
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Determining common ancestor by where descendants match on particular chromosome

Can I tell which ancestor, like a 4th great grandparent by where we match on a particular chromosome? I am trying to find 4th great grandmothers maiden name. I have distant matches with same names ...
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Half siblings connection to another match who is probably a 2C

I am trying to find the relationship of #3 to #1 and #2 #1 is a 20 y/o male with connection to #3 as follows: 299.3cM; largest segment 59.8Q...Total X cM is 109.9cM; largest segment is 66.4cM #2 is a ...
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1 vote
2 answers
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Autosomal DNA match anomaly or false positive?

I've done autosomal DNA tests on ftdna for myself, my mother and paternal grandmother. I've transferred the results to MyHeritage, where I have a match with a person X with the largest segment of 27cM....
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Distinguishing aunt from half sister using X and autosomal DNA [duplicate]

My dad died 4 years ago. But my grandfather (his dad) could be my bio dad. We have made a test with my aunt (his full sister) and we share 25,27% dna (1860,2cM 43 segments max136,2cM) With Geneanet we ...
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Half Sibling/First cousin [duplicate]

From reading many sources, I've discovered that half siblings' shared centimorgans typically range from 1300-2300? And I'm curious about cm lengths in combination with that number. If a person had ...
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Interpreting DNA Match of 947cM at AncestryDNA [duplicate]

I am 75 years old. I have a known 1st cousin who matches 756 cM with me. I also have an unknown 1st-2nd cousin who matches 947 cM with me and is 44 years younger than me. What relation could this 1st-...
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Assessing likelihood of incest using AncestryDNA results

My mother was raped by her father sometime in her adolescence. There was a trial and he was acquitted, but it is generally known and accepted in our family that the rape did occur. I don’t know if the ...
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2 answers
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Determining likely relationship for DNA match of 1,148cM

Was not looking to discover my father wasn't my bio dad. Now I have a match claiming I'm his half- aunt. I'm hoping that I'm NOT his parent’s half-sibling but instead their half-cousin. Is it possible?...
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Using DNA to find biological father

I have done both 23 & me and Ancestry trying to gets leads on who in the world my birth father could be. My mom truly can’t recall. I found a first cousin or potential great aunt I think. She ...
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Making sense of low DNA match for half-siblings

My DNA match on Ancestry was thought to be my half sister. After my test came back, 713 cMs across 20 segments, 10% shared DNA, longest segment 136, that says my Grandfather would be her father, but ...
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How do Genetic Percentages in Common Compare to Possible Familial Relationships?

I recently was contacted about a deceased half-sister who is 11 years older than me. I did a 23AndMe test, and it shows us as 1st cousins with 13.57% shared DNA. An adoption agency lists my mother as ...
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Understanding DNA match of 2,559cM to grandparent

I received my DNA results from Ancestry. My first DNA match ended up being my paternal grandpa. We shared 37 percent of our DNA and 2559cm. If that seems high, what could be causing so strong of a ...
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DNA matches half uncle

I was wondering if anyone could answer this question I have. I have DNA match with my half uncle ( fathers side) , and I also have a half great Aunty - mother’s side. My sister has a slightly higher ...
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Would half siblings share the same DNA links to extended family

I've matched with either a half sibling\aunt or niece on MyHeritage - we chatted and it seems like we share the same father. However, I have links to a 1st cousin once removed or second cousin, for ...
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1 answer
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3rd Cousin DNA with a person

I share a DNA match with a male person of 152cM coming up as a 3rd cousin. I also share a match with his half brother but much Lower at 45cM. These two share the same father but different mothers. I’...
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What is the relationship based on shared DNA

We are trying to find out information regarding my mothers biological father side of the family. My mom was adopted in 1945 and later in life discovered her biological mother but not her biological ...
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1 answer
158 views

Distinguishing half siblings from first cousins (possible fathers are brothers) using shared cM

Regarding half siblings, sent my DNA to Ancestry came to a match of half sibling at 1530 cMs @ 99% half sibling however was in contact with such match and he is claiming my father or one his two ...
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2 answers
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Understanding DNA match of 1,723 cM

I have a DNA match of 1,723 cM with a male 6 years younger than me. His father is one of a twin, could my match be not my half-sibling but my 1st cousin.
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4 votes
2 answers
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Sharing 52% DNA with mother

I received my 23 and me results and it says I share 52% DNA with my mom. Is this possible?
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1 answer
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Understanding relationship with Shared DNA of 1,501 cM across 50 segments [duplicate]

My husband and I recently did AncestryDNA. He came back with a DNA match (shared with his mother) that simply says "close relative". He has no idea who this person is, and his mother claims ...
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1 vote
1 answer
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Half Uncle possibility -fathers side

I recently conducted a DNA test on ancestry.com and I received a strong match with a guy I don’t know . 758cms across 23 segments longest segment 86cm. He is 57 years of age and my father is 70 and i ...
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ALL 23andme matches link via one grandparent?

I have spent hours today looking at my 23andme DNA matches, and while I have not checked every single one, it seems to me that ALL of them descend from ancestors of my paternal grandmother. I am 100% ...
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2 unknown grand fathers

I have known for a long time that my fathers father is unknown. Unfortunately, I have learned that my mothers father is unknown also. I have recently received my DNA results but the nearest match is ...
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2 votes
2 answers
126 views

Shared DNA when MRCAs are Cousins

On average, 2nd cousins are expected to share about 1/16 of their DNA. If parent-child share 3600 cM, then the 2nd cousins would share on average 1/16 of that or 225 cM. The 2nd cousins share a set of ...
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Does DNA match of 1,781 cM suggest half siblings? [duplicate]

I have been contacted by someone who says we are half sisters due to our DNA match. Our DNA is 1,781 which apparently is a high match. Would this make us half sisters? I am an only child and she is ...
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2 votes
2 answers
467 views

Understanding why first cousins may share only 360 cM

I have taken a closer look at the info on my 23andMe match with my known 1st cousin. It says we share 360 Centimorgans, and the Centimorgan charts I've looked at suggest this is potentially outside ...
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Is 1,147 cM match for half sibling or cousin

I have an 855 cM match with a mystery 1st-2nd cousin. My cousin has an 1,147 cM match to the same mystery cousin. Is it possible the 1,147 cM match could be a half sibling?
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Can my half uncle's, half sister be my 1st cousin once removed?

What we believe to be my half-uncle (16% shared DNA | 1,118 cM), has a believed half-sister (1,660cM). My relation to the 'half-sister' is (8% shared DNA | 541 cM) which would most likely make her my ...
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3 votes
2 answers
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An Odd Set of cM Match Amounts

I can't resolve why the following strange set of match results is occurring. We have a fairly simple set of known relationships as shown in this tree: All the DNA Testers are shown in green. Jenny ...
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3 votes
3 answers
202 views

How can two different generations of one family be a half sibling to an outsider?

My full paternal uncle and I enough cM with an outsider to both be listed as half siblings to an unknown male. My uncle shares more cM with that unknown male than I do (a female). Both my uncle and I ...
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5 votes
3 answers
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Clustering of DNA regions at the grand-parents level

My father is born of unknown father and did a 23 and me DNA autosomal test. I thought I could use this test to potentially identify some relatives on this side but only very distant ones (at best 3rd ...
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Full sibling vs half sibling

Initially one of my full siblings and I received dna results from ancestry.com. which showed that our shared dna is 1752cm, and we were matched under close family - 1st cousin. I was a little ...
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2 votes
2 answers
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23andme shows a man as my dad's cousin, but ancestry.com shows him as my dad's brother

I did 23andme, and so did our mystery man. Two of my grandfather's brothers also did 23andme, as well as a number of the kids and grandkids of my grandfather's brothers and sisters (my grandfather ...
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1 answer
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DNA half-sibling

My brother did an Ancestry DNA test last year and last week got notification of a new close relative match. The man matches at 1695cM which indicates grandparent/grandchild/uncle/nephew/half-sibling. ...
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What is the cut off for a half-sibling and first cousin in CM's?

I am adopted and was searching for my birth family and found a cousin and since then I had someone in the family helping me with the search. I found someone who I think is my half-sibling. She did a ...
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Trying to narrow down biological grandfather

I have been working on finding my biological grandfather. The closest DNA match I have to my father (who has taken a test) is 1015cM. I've narrowed down his father to either her father or her uncle. ...
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1 vote
1 answer
246 views

What would the cM range be for persons sharing the same mother and the fathers are brothers?

I had a swab test performed to establish sibling-ship through DNA Diagnostic Center (DDC) wanting to confirm what I thought was certain paternity with myself, male sibling and and mother (father ...
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1 answer
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Can 2,025 cM shared indicate full Siblings?

My brother and I did ancestry tests at different times. We had 2,025cM over 39 segments. Longest one was 158. As I looked at our matches all I could see was my moms side of the family. It was saying ...
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2 votes
1 answer
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Mapping DNA relationships on paper

I have recently started digging into my DNA matches. I have several closely related matches. I was born in Montana and my grandma was married to a man who has no biological relationship to me. However ...
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3 votes
1 answer
469 views

Determining if half brother was product of incest

I have worked on my tree through Ancestry.com for many years to include furnishing my DNA. My brother's daughter started a tree through Ancestry and gave her DNA also; the results shows her as my half ...
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2 votes
1 answer
220 views

Understanding daughter's 314 centimorgans with half nephew

My daughter just learned she shared 314 centimorgans with a boy we believed was her half brothers son. I have just sent in my sample as the supposed father of her 50 year old half brother. We are all ...
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7 votes
3 answers
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Is there anything wrong with using small DNA segment matches as evidence?

Many people find relationships with other people that they only share a small amount of DNA with, e.g., 10 cM or less. They then, after researching the other person's tree, find a common ancestor and ...
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2 votes
2 answers
256 views

AncestryDNA is changing again? What's going on? (July 2020 edition)

AncestryDNA is changing the way they match users, and which matches will be shown to you. Matches that share 6 to 7.9 cM will be eliminated. In addition, since AncestryDNA rounds up segments from 7.5 ...
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