Correction: Help:DNA_Confirmation#Autosomal_Triangulation page

Question

This request is rescinded as it turns out the FTDNA Matrix tool is not capable of comparing matches adequately.

The Help:DNA_Confirmation#Autosomal_Triangulation page currently states that "Family Finder does not allow you to see exactly how your matches match each other on specific segments." which is no longer true with the addition of their chromosome browser. I would like to suggest that the section be updated to replace:

Family Finder does not allow you to see exactly how your matches match each other on specific segments. "In Common With" is insufficient. Consider uploading your results to GEDmatch.com to enable chromosome segment comparisons to be made using their Triangulation utility.

with:

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FamilyTreeDNA: If all the test-takers are on FamilyTreeDNA you can use their chromosome browser and Matrix tool to create triangulation groups. If all test takers are not on FamilyTreeDNA consider uploading your results to GEDmatch.com to enable chromosome segment comparisons to be made.

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or something of that sort. Ideally, the section could be made a bit more consistent:

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23andMe: If all the test-takers are on 23andMe click on "ANCESTRY TOOLS", then click on "FAMILY INHERITANCE ADVANCED". Use the Compare tool to view the segments shared by all the cousins. If all test takers are not on 23andMe consider uploading your results to GEDmatch.com to enable chromosome segment comparisons to be made.

AncestryDNA: AncestryDNA does not allow you to see exactly which segments of DNA are shared by your cousins. "DNA Circles" are insufficient. Consider uploading your results to GEDmatch.com to enable chromosome segment comparisons to be made.

FamilyTreeDNA: If all the test-takers are on FamilyTreeDNA you can use their chromosome browser and Matrix tool to create triangulation groups. If all test takers are not on FamilyTreeDNA consider uploading your results to GEDmatch.com to enable chromosome segment comparisons to be made.

GEDmatch: If all the test-takers have uploaded to GEDmatch, use their "Triangulation" utility or "'One-to-one' compare" utility (for you and each cousin). GEDmatch accepts uploads of DNA files from most major DNA testing companies.

In each case search for segments measuring 7 cM or more that you share (i.e. overlap) with two or more people who are all distant cousins to each other. See here for more information on triangulation.

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Thanks

Answer 1

On FTDNA the Chromosome Browser alone is not enough. Some of the overlapping segments might be from the paternal side and some from the maternal side. You need to use it in conjunction with the Matrix tool.

Comments

Good point, thanks Lynda. I tend to avoid using FTDNA's site whenever possible so I'm not that well versed in their tools. I'll add that to the recommended changes above.

Answer 2

On FTDNA you can use the chromosome browser to check to see if you share the same segment with person A and person B. But you can't check to see if person A and person B match on that same segment. You need GEDmatch to be able to do that.