Wednesday, September 3, 2014

#FGS2014 Conference: AncestryDNA Matches

At the 2014 annual conference of the Federation of Genealogical Societies, Anna Swayne of Ancestry.com presented the session “Utilizing AncestryDNA Matching to Break Through Brick Walls in your Research.” This is the last of three articles about that presentation.

AncestryDNA cousin match listWhen you get your DNA tested from AncestryDNA, you get two types of results: an ethnicity estimate and a report of matches. AncestryDNA compares your DNA to the DNA of the other people, now numbering 500,000, who have submitted DNA. AncestryDNA shows matches based on the amount of shared DNA. Even if you don’t have your results linked to a tree, you will see matches.

If you have your results linked to your tree, even more information is possible. AncestryDNA compares your tree to the tree of each match to find the most recent common ancestor.

Because it provides a link to the tree, some people establish a tree that they use just for DNA matches. It contains just the subset of information they wish to share with their DNA matches.

Swayne showed a fan chart that she had marked up to show the most recent common ancestors she shares with her DNA matches. I’ve shown mine, below. (Apparently, I didn’t inherit the genealogy gene from Grandpa Insider.) Because DNA is lost with each successive generation, it is a good idea to have your earliest living ancestors tested. If your grandparents are all deceased, consider having as many of their children tested as possible. If you have no living parents, consider having your siblings tested in addition to yourself. Swayne has done so and showed on her fan chart the additional matches she found by doing so.

Fan chart showing the common ancestors of the Ancestry Insider's DNA matches.

AncestryDNA might show you lots of matches, so filtering the results is very useful. (See image, below.) One filter is the Hints filter. Pushing this button shows only the matches for which you and the match share a known, common ancestor. Another filter is the favorites filter. Click the star next to a match to add it to your favorites. Click New to see new matches. Visit often; AncestryDNA doesn’t notify you of new matches. It is also possible to attach a note on a match to allow you to remember things about that match.

You may have lots of AncestryDNA results, so filtering is very useful.

AncestryDNA can help you break through brick walls in a number of ways. I don’t remember if Swayne mentioned all of these. (We’re at the point that my memory of what was exactly said is starting to fade.) The most straightforward way is to find a cousin who has already broken through your brick wall. AncestryDNA allows you to anonymously contact DNA matches. You can then compare research notes that may not be available online. If you are African American, DNA can break through the brick wall of establishing the area of Africa from which you descend.

Sometimes DNA doesn’t directly give the answer, but gives you sufficient clues to bust through your brick wall. Even if no common ancestor is found with a DNA match, AncestryDNA displays a list of common surnames in your trees. To identify the matches pertaining to your brick wall, use the search box. It can be found to the right of the filter buttons. (See the image above.) You can search by surname and location to find matches that might pertain to your brick wall. Approximate date is figured using the estimated relationship between you and the DNA match. For example, if AncestryDNA estimates that you are 3rd cousins, then you might share a common ancestor four generations earlier. Using a generation length of 34 years,1 then your common ancestor was born about 136 years ago. If you were born in 1950, your common ancestor was born about 1814. This gives you surname, place, and date in which to focus your traditional research to break through your brick wall.


Sources

     1.  John Barrett Robb, “How Long is a Human Generation?” [website has no title] (http://www.johnbrobb.com/Content/DNA/How_Long_Is_A_Human_Generation.pdf : accessed 30 August 2014). Donn Devine, “How Long is a Generation?” Ancestry, September-October 2005, 51-53; preview these pages on Ancestry Book (http://books.google.com/books?id=JzgEAAAAMBAJ : accessed 30 August 2014), search for “reckon”.

5 comments:

  1. One clarifying point to make is that when AncestryDNA compares your tree to the tree of each DNA match to find the most recent common ancestor, any that is found isn't necessarily the same MRCA that the common DNA segment(s) shared represents. Unlike 23andMe and FTDNA's Family Finder, AncestryDNA doesn't provide the matching DNA segment information or percentage of DNA shared.

    One tool that may help, however, is GEDmatch (http://www.gedmatch.com). It allows you to upload your AncestryDNA raw data to see the matching segment information with those who've also uploaded there, including not only those who've done so from AncestryDNA, but also the other two services. There is no cost to do so.

    Another possible solution is to upload your AncestryDNA raw data to the Family Finder autosomal product at FTDNA (https://www.familytreedna.com) at a reduced rate from testing there from scratch. It then takes several days to see results. 23andMe may well still have a larger autosomal database than AncestryDNA and FTDNA (FF) combined, so testing there is also a must for those who wish to have as wide a presence as possible. It doesn't allow uploads from the other services (nor does AncestryDNA for that matter).

    A tool to help make sense of the many matches generated is the AncestryDNA Helper extension on Google Chrome (https://chrome.google.com/webstore/detail/ancestrydna-helper/hjflmfphflaeehhpdiggobllgffelfee). It provides additional functionality that AncestryDNA doesn't.

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  2. Romer makes very good points. AncestryDNA is only giving us part of what is needed to verify matches. We need to see the actual chromosome segments to verify a match and pretending otherwise is just wrong. We shouldn't have to depend on posting results to a free site that is very overloaded (GEDmatch) or pay even more money to transfer results to another DNA testing site (FTDNA) in order to verify our AncestryDNA results.

    It is long past time for Ancestry to give us a chromosome browser directly! Customers have been asking for this since the very beginning. And, who knows how many customers are lost because that feature is not available.

    There are plenty of well-educated people who can help if help is needed to figure out how to do it.

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  3. I completely agree that Ancestry should provide a chromosome browser as well as a triangulation tool to identify matches in common. I do give them credit for recently allowing DNA matches to be shared similar to the way trees can be shared. I've done this with a cousin of mine. We share one common line. By identifying the matches that she and I both share, I can be pretty sure which ancestors we have in common with the third match. I'm not comfortable sharing my DNA matches with a stranger but doing so with someone I've known all my life has its perks.

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  4. What the previous commenters said: why no chromosome data? Ancestry just stonewalls this question.

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  5. Spread the word on the need for transparency with matching segment data:

    http://dnagenealogy.tumblr.com/post/96078332683/tell-ancestrydna-free-our-matching-segments-to

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