Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [dna]

For questions about using DNA to further knowledge of family history, relationships, ethnic origin, and overall ancestry. Most common tests include Y-DNA, mitochondrial DNA, and autosomal DNA.

0
votes
0answers
25 views

DNA not supporting linear genealogy between grandparent, child and grandson?

I am his grandmother and should have 300 or more cMs connection. However, we share only 18 or so cMs. My son, (my grandson's father), shares only 17.2 cMs. What's up?
0
votes
2answers
26 views

Interpreting 23andMe results for half siblings that share 45.5% of their DNA?

I was raised to believe that my half sister and I were in fact half sisters with different fathers. We both did 23andMe testing and the results conclude that we share 45.5% of the same DNA. we share ...
-7
votes
0answers
14 views

This is about my labradore [on hold]

In order to breed my dog with a certain female he needs to be seven generations away from a certain stud dog whos genes did not work well with this female. Pups had some kidney problems.. After ...
2
votes
2answers
39 views

No shared X DNA segments found

On FTDNA I match two other Stephens males with the exception of 1 marker over 67 markers. When the three of us uploaded our DNA to Gedmatch, mine from FTDNA Family Finder and theirs from Ancestry, we ...
2
votes
1answer
40 views

Are centimorgan contributions additive?

I share a 50 centimorgan 6 segment match to person "J". My maternal side aunt shares 54 centimorgan 5 segment match to that same person "J" I see two possible blood-line connections between my aunt ...
0
votes
0answers
43 views

Is aunt actually mother's half sister?

I was looking at a first cousin of mine after doing the 23andme DNA test and found that we only share 5.25% of DNA with him, and it believes he is a second cousin of mine. I checked my mom's DNA ...
1
vote
1answer
35 views

Determining if siblings are half siblings or full siblings?

I recently found 6 siblings 4 who are half and 2 who may be full. My sister was born in 1949, I was born in 1950 and my brother in 1952. The other siblings all know who both their parents are. The ...
6
votes
1answer
51 views

When triangulation is not transitive

I'm focusing on triangulation groups and so looking at matching segments that overlap each other. I'm frequently finding the situation where, at a single website, match A's segment is shown as ...
5
votes
1answer
47 views

Segments with no matches

I am beginning the process of forming triangulation groups, and I wonder: what do people do with segments on which there are no matches? I found such a segment already just on the first chromosome I ...
0
votes
0answers
18 views

Does 2% fall into the normal range of amount of DNA shared with a first half cousin? [duplicate]

Does 2% or 142 cm amount of DNA shared with a half first cousin add up? From what I’ve read, the amount of DNA shared between two half first cousins falls between 215-650 CMs or 4-7%. My other ...
6
votes
1answer
104 views

Reconstructing autosomal genomes of Mayflower passengers

I imagine no group of 100 people has been as genealogically documented as the Mayflower passengers. And with an estimated 35,000,000 descendants living today, the number of descendants genetic tests ...
0
votes
1answer
32 views

DNA results for half sibling

I had my DNA test done about 8 years ago with ancestry, I was contacted by a person who believed he could be my half brother from my father during World War 2, all the information he had said my ...
1
vote
2answers
59 views

Half sibling or 1st cousin?

I recently did Ancesty DNA to determine a match between me and a possible half sister. The results came back, and we share 1366 cM of DNA. As I’ve learned, this is on the low side for half siblings ...
4
votes
1answer
34 views

Percentages of nucleotides in raw DNA

I just had Excel compute the percentage of each nucleotide appearing as the first letter in each position in a raw DNA file. Then I had it compute the percentage of each nucleotide in the second ...
4
votes
2answers
73 views

Triangulation conundrum

I tested both my mother "M" and her brother "D" at FTDNA. I was looking through D's list of segments today for triangulated segments, using the matrix utility to help, and I found the following D ...
3
votes
1answer
45 views

Are there different amounts of “fuzziness” in the endpoints when doing pairwise 1-1 comparisons among three people at GEDmatch?

I was performing a triangulation at GEDmatch and obtained the following start and end points for the triangulated segment on Chromosome 1 for each comparison: Person A with Person B: 19,899,991 ...
0
votes
1answer
33 views

Centimorgans shared with a great unclie

I have a 1400+ centimorgan Match to a great uncle on my father's side. Is it common to have this strong of a match to a great uncle? I have read this high number is usually shared with half-siblings,...
0
votes
1answer
57 views

Half Uncle Mystery

I discovered a match on ancestry.com that was a first cousin match to me on my fathers side but assumed it was his half sibling (we suspected existed.) We share 756 centimorgans. He is five years ...
8
votes
0answers
43 views

Is Whole Genome Testing in any way useful for Genealogy?

There are several DNA testing companies out there that are excellent for genealogists. These include Ancestry DNA, Family Tree DNA, MyHeritage DNA and 23andMe. These companies provide match lists of ...
5
votes
1answer
50 views

Phased psuedo-kit on GEDmatch — what accounts for huge drops in SNP count?

I guess first I should make sure I understand how GEDmatch stores raw data -- I'd guess that during "tokenization", GEDmatch turns my raw data file into a format that it likes, i.e., perhaps replacing ...
2
votes
1answer
69 views

DNA results from Ancestry

A friend of mine took a DNA test with Ancestry.com a while back. Now I (a trained mathematician) am being asked to help interpret the results, and I am finding myself totally out of my depth. The main ...
1
vote
2answers
74 views

Is this close family member on AncestryDNA a half sibling?

on ancestry.com i got a "close family" match, with 1,430 centimorgans shared across 58 DNA segments - it says it could be a niece, aunt, or half sibling (range includes 1st cousin, but i have read ...
3
votes
1answer
102 views

Why would I match someone in a region neither of my parents do?

I was surprised to find someone show up in FTDNA as a 2nd-3rd cousin to me (168 shared cM, 34 segments with a minimum length of 5 cM) but not among the 17,667 matches of my father or the 18,178 ...
-2
votes
1answer
40 views

half-sibling's child listed as 1st/2nd cousin

A child of a half-sibling has been determined to be a 1st or 2nd cousin; and the explanation is that variability to four degrees. Is it possible that the half-sibling status with his mother creates ...
0
votes
1answer
39 views

Finding biological father and half siblings in Spain using DNA?

I am 56 years old and I recently received negative paternity results from a spanish court appointed lab in Sevilla , Spain regarding half siblings, biological father is deceased. My mother will not ...
1
vote
1answer
43 views

Evaluating Ancestry DNA match to clarify Half Sibling relationships?

I did the Ancestry DNA an had a match of 1671 to a person I did not know. My sister did the test and matched him at 1251. My father believes he has a son he does not know and the stories seem to add ...
0
votes
1answer
95 views

How to help adoptee find her father without outing him?

I provide a lot of background, which may not all be essential. Feel free to skip to the question. Background I was contacted by a woman who got a 3rd cousin match with me online. She told me that ...
2
votes
1answer
149 views

Is this a half niece/uncle relationship vs 1st cousin once removed, or something else?

I've been in search of my deceased father's biological family. He was placed for a closed adoption 60+ years ago. I've discovered the two families who parented him thanks to Ancestry DNA matches. ...
0
votes
1answer
68 views

How does this cousin have NO relation to other cousin? [closed]

My husband and two of his cousins had their DNA done. Cousin A comes back as 1st cousin (as he should) cousin B comes back as distant 6th-8th cousin. Cousin A and B have NO relation. Cousin B ...
0
votes
1answer
108 views

Can half-siblings show different relationships to extended family?

My husband has found a half sibling, first on Ancestry showing a match of 1542 cm over 77 segments, and then confirmed on 23andme with a suggested relationship of "half sibling". Ancestry only showed "...
0
votes
1answer
43 views

Using DNA to prove parentage?

I am the biological mother of a woman born in 1967. To substantiate birth records for her and to prove that I am her biological mother, what is BEST DNA testing?
4
votes
3answers
109 views

Strategies for finding biological grandparents using DNA matches?

I need some advice to help track down my biological grandmother. My father was adopted in 1920 and died in 2000 without knowing the identity of his biological parents. I have his birth certificate but ...
4
votes
1answer
180 views

Total centimorgans vs shared dna segments?

What is the relevance of the amount of shared DNA segments? Example: I have a match that is from my adopted grandmother's family. The match shares 167 cMs over 12 DNA segments. I typically use DNA ...
3
votes
1answer
92 views

Taking endogamy into account when analyzing DNA matches?

How can I be certain how closely I actually relate to my cousin matches when I know that I have a person in my tree who is my 4th Great Aunt on my Father's Maternal side. This same person is possibly ...
0
votes
1answer
49 views

Identifying which husband of my great grandmother my father came from

My father was adopted. I believe that I have located his mother. Her father is my GREAT GRANDMOTHER's first husband. I have tested 3 1st cousins once removed??(Female 1 cm=673 on 29seg/female 2 cm=...
0
votes
1answer
40 views

What type of DNA test?

I have done an Ancestry.com DNA test that revealed 32% Native American. I was looking for a specific region or tribe--searching for my great-grandmother, who was native american. my grand father is ...
6
votes
1answer
58 views

Is longest cM a better predictor of relatedness than total cM for Ashkenazi Jews?

As an Ashkenazi Jew, I'm used to matches being predicted to be closer than they really are. My father recently got a match to an adoptee of 348.3 shared cM, with a longest segment of 57.4 cM (...
3
votes
1answer
108 views

How to interpret my having ethnicities inconsistent with my parents?

According to MyHeritage's interpretation of our 23andme lab results: My father is 93.7% European (90.5% Ashkenazi, 2% Baltic, and 1.2% Italian), 5.5% West Asian, and .8% Central Asian. My mother is ...
0
votes
1answer
77 views

How likely is it that I am related to a specific person who was living 20 or 30 generations ago? [duplicate]

I have discovered that I am related to someone specific who lived in 1066. How likely is this? In other words, the answer could be “No big deal. When you go back that many generations,the math shows ...
1
vote
1answer
43 views

find relatives in-common or not-in-common based on multiple people?

Out of the hundreds of DNA relatives that show up I only recognize a few. My paternal grandfather's side is a complete mystery; I haven't found one person I recognize from what I know of my family ...
1
vote
2answers
68 views

Different genetic relation strength through maternal vs paternal line?

Is there a different genetic relation strength through maternal vs paternal line? In other words: am I more related to my mother than to my father or are they exactly equal? Or another way to ask it ...
1
vote
1answer
51 views

Using DNA data on different genealogy sites?

I had my DNA tested through a third party, independent (i.e.: not one of the main genealogy sites) lab. I have my results from them but want to upload them to the main site that I use (myheritage.com, ...
6
votes
4answers
148 views

Is birthmother sharing only 1549 centimorgans possible?

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 ...
5
votes
2answers
71 views

Using “shared DNA” column in 23andme for triangulation?

On the 23andme site when you compare dna with a relative there is a column labeled "Shared DNA" and the description on their site says Shared DNA means that you and your two genetic relatives share ...
5
votes
1answer
133 views

I'm a 2nd cousin to someone, my brother is a distant cousin?

My brother and I have both been tested on 23andme. There are many people that show up at different relationships and I'm trying to understand how there can be large differences in predicted ...
2
votes
1answer
63 views

Seeking tools to analyse 23andme raw data?

I recently got my ancestry genetic test done from 23andme. I am interested in finding out more about my raw data. Does anybody know of some good tools that come for a good price and give me the ...
1
vote
3answers
432 views

Half Siblings not showing up as DNA matches?

I am managing the DNA accounts of my adopted brother. He has been tested directly with Ancestry and 23andMe. In 2017 FTDNA was allowing users to upload their raw dna data for a fee, and they would be ...
7
votes
1answer
94 views

Explaining major discrepancy in genomic position between Gedmatch and MyHeritage?

I have identified a discrepancy with several test kits that were tested at Ancestry, with results transferred to both Gedmatch and MyHeritage, all relating to the same area at the end of chromosome 19....
8
votes
3answers
103 views

Using shared cM to determine likelihood of misattributed paternity?

My ancestor Harriet Smith was born in the mid-1850s in England. Her birth certificate shows both of her parents (John Smith and Sarah Johnson). For the purposes of the birth registration, John and ...
3
votes
1answer
83 views

Are We Closer Kin Than First Cousins?

I had a match on Ancestry of a lady who was adopted as a baby, who is looking for her birth parents. She is my age. She matched at 1111 across 45 DNA segments! I know that is in range that is more ...