10 votes
Accepted

Explaining major discrepancy in genomic position between Gedmatch and MyHeritage?

It looks like this may be due to a difference in the Genome Builds (https://en.wikipedia.org/wiki/Reference_genome#Human_reference_genome) used between the two tools. GEDMatch reports that they ...
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7 votes
Accepted

What does 'DD' mean in a name on GEDmatch.com?

The "DD"-prefix simply means that they're a member of the Facebook group "DNA Detectives". It's a Facebook group for people who use DNA genealogy to track down family members. If you're on Facebook, ...
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  • 5,167
6 votes
Accepted

How does the GEDMatch Relationship Tree Projection Tool Work?

The GEDmatch Relationship Tree is a wonderful idea the imaginative people at GEDmatch put together. No, there is not much documentation about it and it is still said to be a "work in progress", but it ...
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  • 16.5k
6 votes

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

What I see often said is that any matching segments under 5 cM, if not under 7 cM, are more likely to be identical by chance rather than by descent, and should usually be disregarded as noise. A ...
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6 votes
Accepted

maternal haplogroup and X-DNA Comparison: is this likely a relation?

mtDNA and X-DNA mostly are not related. If two persons share the same mtDNA haplogroup it just means that their common direct maternal ancestor lived ~10000 years ago (when this haplogroup was ...
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  • 1,075
6 votes
Accepted

Why are the lengths GEDmatch.com Chromosome Segment Matching segments not proportional to their cM?

The colored segments are not drawn in terms of cM, but in million base pairs (Mbp), which are the number shown on the bottom of your graphic. The numbers at the bottom are very approximate in position....
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  • 16.5k
5 votes
Accepted

Why is GEDmatch report omitting some matches?

There are 46 chromosomes that come in 23 pairs, one from mother and one from father. You are talking here about chromosome pair 12. The way matching works is that it cannot determine whether the ...
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  • 16.5k
4 votes

Which Gedmatch admixture calculators are most useful for an individual of predominately African American descent?

For your African ancestry, accounting for European: in project Dodecad, try calculator Dodecad V3 in project Ethiohelix, try EthioHelix K10 + French in project GedrosiaDNA, try calculator Gedrosia K3 ...
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  • 16.5k
4 votes

Why is the total shared Centimorgans 52.7%?

The different companies use different cM for the 22 chromosome pairs. GEDmatch's total is 3587 cM excluding X and Y. See http://isogg.org/wiki/CentiMorgan Note this is half of what the 44 chromosomes ...
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  • 16.5k
4 votes
Accepted

When will early 2016 23andMe kits be uploadable to GEDmatch.com?

GEDmatch has two ways of getting the raw data from 23andme. If one of them doesn't work, the other one might. There have been no changes to the data format that GedMatch can't handle. One way is a ...
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  • 3,857
4 votes

Finding out which DNA matches are from paternal side?

legacyfamilytreewebinars.com ran two fairly recent webinars that might be extremely useful to you, "Weaving DNA Test Results into a Proof Argument" by Karen Stanbury, and "Finding Missing Persons With ...
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  • 2,569
4 votes

How can overlapping ~35 cM segments of matching kits not match each other?

The simplest and most likely cause of the lack of a match is that Alice is related to Bob and Charlie through different parents. If Alice inherited the 36 cM of DNA she shares with Bob from, say, her ...
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  • 3,857
4 votes
Accepted

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

So what you've got is this: You are correct that there is a single segment, represented by the dark blue segment in the diagram, between 30 and 35 Mbp (Mega base pairs) that is the triangulating ...
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  • 16.5k
4 votes

Finding Korean War-Baby Brother using GEDmatch?

Getting your DNA tested and uploading the data to GEDmatch.com were both great ideas for trying to find your half-brother. According to https://www.nytimes.com/2016/08/28/world/asia/south-korea-...
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  • 835
4 votes
Accepted

What relation is my Half-Aunt to her DNA Matches?

The advantage of more people testing is that you can use the cM ranges better. Here, your aunt matches full siblings with different cM totals, even though they have to be the same relationship to her....
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4 votes
Accepted

How to completely upload an "Everything" kit created from Dante Labs to GEDmatch?

Ignore the cM value offered by the One-to-One tool, as a cM is just a STATISTICAL APPROXIMATION, instead check the offered SNP comparison values, it should read: "100 Pct SNPs are full identical&...
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  • 171
3 votes

maternal haplogroup and X-DNA Comparison: is this likely a relation?

A match on maternal haplogroup may indicate a common ancestor on the direct maternal line (mother, mother's mother, mother's grandmother, etc). The inheritance pattern for the X chromosome is more ...
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3 votes

"non-zero cM for X" result needed for GEDmatch Relationship Calculator?

I assume you're talking about the 'Tier 1' Relationship Tree projection tool. Not many of us are gedmatch.com Tier 1 subscribers. But a non-zero CM result for X is self-explanatory. The 'X' refers to ...
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3 votes

What explains sharing a 28.6 cM DNA segment with a sixth cousin?

We all have about 3400 cM of DNA. On average half gets passed down each generation. So on average 1700 goes to a child, 850 to a grandchild, etc. Sixth cousins are at the 6th generation, so every 6th ...
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  • 16.5k
3 votes

How to upload a "stripped" GEDCOM to DNA sites

Family Historian has a gedcom export plugin available that has a specific export option for this scenario. However, the free trial version does not allow the running of plugins and so may be an ...
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  • 3,808
3 votes

How do I convert my RAW FamilyTreeDNA FamilyFinder test result files to Ancestry or 23andMe format?

This is an extended walk through of the original high level walk-through (no screenshot and only for windows) posted by Steven Frank's Blog for Windows PCs of a way how to do this to convert it to ...
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  • 5,531
3 votes
Accepted

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

GEDmatch does not disclose its methodology for phasing at GEDmatch Genesis. But if you and your mother tested at different companies, especially different companies that use different chips, then it ...
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  • 16.5k
3 votes

Identifying maternal grandfather through autosomal DNA testing?

It will help if your father is still alive and willing to test. If not, consider his siblings or your first cousins on that side. Your best hope is to find DNA first or second cousins, but work ...
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2 votes
Accepted

What explains sharing a 28.6 cM DNA segment with a sixth cousin?

You might want to look over this blog article: Genetic Genealogy and the Single Segment. It discusses a few points one might want to consider when one matches another person on just one segment. One ...
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  • 3,857
2 votes

Half sisters or aunt/niece relationship?

You are right to suspect an Aunt/Niece or Half-Sibling relationship based on 1786.1 cM Estimated Autosomal DNA matched. You haven't specified if you know who your mother is too, but if you do, or ...
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  • 1,410
2 votes

How do I convert my RAW FamilyTreeDNA FamilyFinder test result files to Ancestry or 23andMe format?

I want to append to the answer that GEDMATCH now supports FTDNA's format (both - b36 and b37). And there is no need in conversion. But if you really need the conversion between the formats there are ...
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  • 1,075
2 votes

Finding out which DNA matches are from paternal side?

If you order a 23andme kit for yourself and can get one of your first cousins or a sibling of your mom to also submit a 23andme kit, you can deduce which cousin matches might be related to you through ...
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  • 29
2 votes

How to upload a "stripped" GEDCOM to DNA sites

If you know a programming a little bit (or better :-) you can use your skills to write simple parser. The best choice is to use language like python and already finished module for GEDCOM parsing (...
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2 votes
Accepted

How can overlapping ~35 cM segments of matching kits not match each other?

This can happen even with full siblings of the same parents. Each parent has a chromosome 18 from each of their respective parents (the grandparents). Let's call the father's pair 18pp (paternal-...
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  • 2,569

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