Are my 23andMe and AncestryDNA results useless for DNA confirmation?

+19 votes
1.5k views

I don't understand how DNA confirmation works. Can you use 23andMe or AncestryDNA results to help confirm relationships? On 23andMe, I've had both myself and my grandma tested, so shouldn't that give me mtDNA? And I've also had my dad tested, so shouldn't that give my yDNA?

WikiTree profile: Tanya McLauchlan
in Genealogy Help by Tanya McLauchlan G2G3 (3.9k points)
If you are female, you don't GET any yDNA, your father has yDNA because he is male, but you get only HIS X DNA component.  If you get his yDNA, you are male.

6 Answers

+18 votes
 
Best answer
When you look at your 23andMe Autosomal test results, these are often good at confirming a DNA relationship. When you compare your results with your Father's and Grandmother's there will be a large number of matching segments on the different chromosomes.

The greater the number of matching segments, the higher the likelihood of a close relationship.

If you read this http://www.isogg.org/wiki/Autosomal_DNA_statistics page, it gives you some numbers that can show the closeness for a match. Bear in mind that there is room for variation. Sadly the numbers of shared cM's is not a hard and fast rule. The second chart gives you an indication of the ranges that each relative could fall into.

Y-DNA and mtDNA don't really confirm a relationship, but do confirm that there is no relationship when they are not the same. Perhaps have a read of this http://dna-explained.com/2014/03/24/haplogroup-comparisons-between-family-tree-dna-and-23andme/ page for an explanation of haplogroups.
by Simon Canning G2G6 Mach 2 (23.8k points)
selected by Lynden Rodriguez
+16 votes

Dear Tanya,  The "confirmed with DNA" notation on WikiTree requires triangulation of shared segments and a notation in the biography section of each profile detailing the triangulation. If gramma was the mother of your dad, you should be able to triangulate the three tests and use the "confirmed with DNA" notation for grandma and your dad.  

Please include a note in the sources section of each biography that explains the triangulated DNA segments.  You can get more information on our http://www.wikitree.com/wiki/Confirmed_with_DNA page.  

by Kitty Smith G2G6 Pilot (634k points)
Hmmm, I thought triangulation was only required beyond third cousin relationships.  Third cousinn and closer should be a slam dunk.
Oh, I forgot about that.  I don't have any close DNA relatives so I always include a citation.
Well, a citation IS needed for relatives both near and far but triangulation only for those that are farther than 3rd cousin.
+13 votes

As others have indicated, the autosomal DNA information from 23andMe can be used to help confirm relationships.

Your mtDNA haplogroup from 23andMe also is good information that could help confirm relationships. For example, I've found that my haplogroup of H1e is not particularly common. Thus, if another person whose genealogy indicates that we have the same maternal-only ancestry has that same haplogroup, I'd consider that to be a strong indication that we truly are related. Even more importantly, if a person whose genealogy indicates that we should share mtDNA turns out to have a different haplogroup, I would figure that there is an error in one of our family histories, or a non-parental event somewhere in our families that we need to investigate.

Unfortunately for those of us who tested at 23andMe, WikiTree only shows mtDNA and Y-DNA information on profiles if the test was one that also screens for additional mutations that can provide a more refined analysis of ancestry (for example, to estimate the generations to the last common ancestor for two men who have the same surname and the same Y-DNA haplogroup). To my mind, this is a bit like creating a database of people in the U.S. that lists them by zipcode, but only including 9-digit zip codes (which are typically specific to a small block of addresses on a specific street) and refusing to include records with 5-digit zip codes (which identify the town or the section of a larger city).

PS - I uploaded my 23andMe mtDNA raw data to http://dna.jameslick.com/mthap-new/ and got back some results that list the markers that were used to classify my mtDNA haplogroup. From mtDNA databases I've seen on the internet, I've seen that all people who have my same haplogroup have several markers in common, but there are some other markers that only some H1e-ers have. If I ever find a possible maternal-line relative (other than the close relatives whom I know) who has my haplogroup, I'll want to compare those other markers with them to see if we have the same combination.

by Ellen Smith G2G Astronaut (1.5m points)
edited by Ellen Smith
This was a great step by step help! Thank you.
+10 votes

tl;dr

Yes (23andme) and no (AncestryDNA)

 

Long version:

As others rightfully pointed out triangulation is the key task to be performed. 23andme has it's own tool (Family Inheritance) whereas AncestryDNA has decided not to give such a tool to it's user (despite many of them complaining and explaining their wishes to have one). So with AncestryDNA you don't get the right tool nor the right data to do triangulation.

Before everyone is shouting out "That's wrong, you can move your data to GEDmatch") let me explain a bit more. Yes, you can but that still doesn't help you if your fellow possible DNA cousin on AncestryDNA isn't doing the same, right? Yes, you might be lucky and you find another two matches at GEDmatch that triangulate but that's a very minor chance (I still have a lot of segments with only one other person matching, not the required two).

As for the detailed question about mtDNA and Y-DNA the short answer is no. The long answer is that you get an estimation from 23andme which is quite good but it's based on an outdated haplotree. Yes, you can download your raw data and check it against other tools to see where in the newest tree you end up (this is how I came up with my mtDNA and Y-DNA) but keep in mind that not all SNP's are tested at 23andme or AncestryDNA.

Furthermore you can't compare it against mtDNA and Y-DNA tests from FTDNA (the only place to buy and test for both) as they are based on a different method (in case of Y-DNA that is STR - short tandem repeat) and as I said you lack the data points to compare against the Y-search and mtDNA search pool (forgot the name - can some add it as a comment?).

Hope this explains it well enough, otherwise please ask questions if points are unclear, happy to help

by Andreas West G2G6 Mach 7 (73.9k points)
+11 votes
Only men have Y-DNA, so you don't have your dad's Y-DNA.  Women get an X chromosome (one each) from their mother and father.  Men get an X-chromosome from their mother and the Y-chromosome from their father.  If you had your father's Y-DNA tested, then you can enter his results on his profile.

There are different types of DNA tests:  Y-DNA, mtDNA, and auDNA (autosomal).  You can take any or all of them.

AncestryDNA will give you clues to help you confirm relationships, but you would have to transfer your results from there to Gedmatch.com (free to do so) in order to actually see what chromosome segments you match with others and work to triangulate and map your chromosomes in order to confirm relationships.  Along with Gedmatch, you can download and use a program (again free) such as GenomeMate or online sources such as DNAGedcom to help locate triangulated groups and map chromosomes.  Once you work on doing that, you can show confirmed relationships on Wikitree.
by Darlene Athey-Hill G2G6 Pilot (530k points)
+10 votes
Thank you for all the answers so far. I feel like such a moron, but I have a REALLY hard time understanding the technical aspect of DNA stuff.
by Tanya McLauchlan G2G3 (3.9k points)
I am right there with you.  When I have 'good' or better matches in Ancestry.com I work on the genealogy and see if I can find how the families connect.  I understand that several people's genealogy could be wrong and we match, but the genealogy is not as it appears.  Hope this made sense.

Laurie

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