DNA Testing for Genealogy – Getting Started, Part Four

Posted August 8, 2012 by Geni | 10 Comments

We’re excited to bring to you a special guest series by genetic genealogist CeCe Moore. Some of you may recognize her from her popular blog  YourGeneticGenealogist.com. She’ll be providing a great overview about DNA testing for genealogy. Here’s the final installment of her very informative series. Enjoy!

We have covered the three types of DNA tests for genealogy over the last few weeks, but there is one more aspect of genetic genealogy that should not be overlooked. In fact, one of the questions that I am asked most frequently is: How can I get a percentage breakdown of my ethnicity? With popular television programs recently highlighting this compelling area of genetic genealogy, it is no surprise that interest in DNA testing has grown.

Percentages and Pie Charts

Many viewers of “Finding Your Roots with Henry Louis Gates, Jr.” were intrigued with the pie charts presented to each guest breaking down their ancestral origins by percentage. These charts were made using data from 23andMe and Family Tree DNA’s autosomal DNA tests. “Who Do You Think You Are?” offered a sneak peak at Ancestry.com’s version (available by invitation only) and the blogs have recently been abuzz with the news that National Geographic has started taking orders for, perhaps the most advanced version yet, the new Geno 2.0.

Percentages of Ancestral Origins, Family Tree DNA’s “Population Finder” 

I find that this subject fascinates most people and is a really fun way to engage non-genealogists. So, even if your family members’ eyes glaze over at the mention of traditional genealogy, you may be able to interest them in DNA testing by talking about this feature.

In spite of its growing popularity, I would be remiss if I didn’t tell you that this area of DNA testing for genealogy still has a long way to go. As many customers have discovered, comparing across companies will often yield different results for the same person and it is difficult to determine which one is the most valid.  For now, a good rule to go by is the more conservative the estimates are, the more accurate they are likely to be (as long as they are from a respected company). In other words, if the report includes only a few populations, you can feel pretty confident about its conclusions. This is because it is relatively easy to tell a person that they are, for example, genetically 100% European.  However offering more detail, such as percentages of British, French, Scandinavian and/or German, remains a challenge.  As a result, I read lots of comments from genealogists who are puzzled by their results. If you receive an unexpected report, please don’t think that you need to throw out your years of research or worry that you may have been adopted! For now, regard this aspect of your results with a grain of salt. Hopefully, with the refining of the tools currently out there and the new offerings on the horizon, we will soon see promising strides in this area.

Put simply, these tests work by comparing your DNA to reference samples gathered from around the world and determining which of these your DNA most closely resembles. Since the sample coverage is still relatively insignificant on a global level, it follows that this science will undergo enormous advancement as an increasing number of people are tested from around the world.

Summary

Do you remember the questions I posed in the first part of this series? Let’s review them in light of what we have discussed over the last month:

Q: Are you primarily interested in researching your surname?

If the answer is yes, then consider a Y-DNA test. If no, then consider an autosomal DNA test.

Q: Are there specific brick walls that you wish to target with the use of DNA testing?

If yes, then see the next two questions.

Q: What is the ancestral pattern back to these brick walls?

If the brick wall is on your direct paternal line, then choose a Y-DNA test and if it is on the direct maternal line, choose a mtDNA test. If it is any other pattern, such as your mother’s father’s mother’s line, then either do an autosomal DNA test or find an appropriate direct line descendant to take a Y-DNA or mtDNA test.

Q: How far back in your family tree are these brick walls?

If the brick wall is within the last five or six generations, consider an autosomal DNA test. If further, then attempt to find an appropriate direct line descendant of the person in question to take a Y-DNA or mtDNA test.

Q: Are you ready for a long-term project or do you desire quick answers?

If you are looking for quick and easy answers, then DNA testing for genealogy may not be right for you. If, on the other hand, you are prepared to embrace a long-term project, then let me welcome you to the fascinating world of genetic genealogy!

Q: Are there adoptions in your family tree that you would like to explore?

Female adoptees should take an autosomal DNA test.  I recommend that male adoptees first take a Y-DNA test to attempt to determine their genetic surname and then an autosomal DNA test to explore the rest of their heritage. If you have an adopted person in your family tree within the last few generations, then either attempt to find a direct male descendant for Y-DNA testing (if male) or order an autosomal DNA test for the person most closely related to that adopted person. Nothing is guaranteed, but as the databases grow testing will become increasingly informative, resulting in more frequent success stories.

Q: Is your primary interest receiving a percentage breakdown of your overall ancestral origins or “ethnicity”?

Order an autosomal DNA test like 23andMe, Family Tree DNA’s “Family Finder”, AncestryDNA or the new Geno 2.0.

I hope you have enjoyed learning about DNA testing for genealogy and are encouraged to give it a try.

Resources to continue your learning:

  1. Join the International Society of Genetic Genealogy (ISOGG). It’s free!
  2. Join the ISOGG DNA Newbie Yahoo Group. Ask questions!
  3. Follow my blog: Your Genetic Genealogist.

CeCe Moore is a professional genetic genealogist and writes the popular blog Your Genetic Genealogist. She is the Southern California Regional Coordinator for the International Society of Genetic Genealogy and the administrator of the organization’sDNA Newbie Yahoo Group. CeCe serves as an “Ancestry Ambassador” to 23andMe and on the advisory board of the Mixed Roots Foundation and is a member of Mensa. Her favorite genetic experiment is her seven-year old son, Nicolas.

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  • IsraelP

    CeCe, you have been great with both guidance and encouragement.

    I still don’t feel I know what I am doing, but like the bumblebee which did not study aerodynamics, I am making significant progress nonetheless. I have posted the first part of a three-part blog on my DNA project and will be presenting a Power Point later this week to family members, which I hope to make into a lecture.

    I do plan to join the ISOGG, but want to get a better handle on the nitty-gritty first.

    I’d love to see you blog on DNA testing as a proof in a genealogy database. When is it proof and when is it just a strong indication. And who decides?

    • CeCe Moore

       Thank you, IsraelP! It is great that you are passing the knowledge on and I hope your relatives enjoy the presentation.
      You don’t have to know anything specific to join ISOGG! It is for anyone interested in the subject. Everyone is welcome!
      DNA testing as genealogical proof is a still developing subject that I don’t think anyone has addressed formally yet. Like I said above in  my last comment, Y-DNA cannot give a specific relationship, so it would be difficult to use it as proof except when the question is “Are these two families related?” An exception to that would be when a very thorough surname project has been able to determine the exact mutations that occurred on specific ancestral lines – like the different sons of a progenitor. It can certainly be used to disprove a relationship!
      Autosomal DNA does have the potential to be used as “proof” in close relationships because it is so good at determining exact relationships. If it is being used beyond five generations, one must be cautious, however it can certainly be used as a strong indication in certain situations just beyond that. As far as who decides…there needs to be a strong set of “rules” set out to follow for the very confident situations. For the more complicated applications, it will be very difficult to determine “who decides” since the majority of genealogists do not have the genetic genealogy knowledge to understand the implications when the proof is laid out in front of them. As DNA testing is increasingly used, we will have to spend a lot more time looking at this issue. Good question!

  • Ss Shuford

    We are trying to break a brick wall in a direct paternal line.  We have done y testing on the oldest male of the line.  From him, the unknown father is 4 generations back, i.e. his gg grandfather.  You state that autosomal testing is preferred if the brick wall is within 5 or 6 generations.  I am not sure I understand why that is the case.

    • CeCe Moore

       @47f4f29d2a588316e65d95e4164f6f36:disqus – It is a complicated question which depends on several factors. For direct paternal lines, Y-DNA testing would be my first choice if you are trying to determine a likely surname and you can locate an appropriate male to test. However, if one can’t be tested, then I recommend autosomal DNA testing if it is within 5 or 6 generations. Autosomal DNA testing is great for really close relationships like trying to find an unknown close relative, like a grandparent or to test out a theory like determining if two people are related within five generations. You have done the appropriate test, but if you don’t find the answer, you may want to supplement with atDNA testing. Y-DNA can definitely help find your direct paternal ancestors, but in your case, since the brick wall is relatively close, atDNA testing may give you a more exact relationship. For example, a Y-DNA test can tell you that someone is related to your direct paternal line, but not how closely because the Y chromosome can be passed down virtually unchanged for generations. Therefore, a 67/67 match on Y-DNA could mean brothers, father/son, grandfather/son, 2nd cousins, 6th cousins or beyond. An atDNA test can determine the exact relationship up to 2nd cousins confidently and 3rd cousins much of the time. So, if you tested this person’s atDNA, it is possible that they might match someone as a third cousins who shares the same gggrandfather. Since I don’t know all of the factors and every case is different, that is the best explanation I can provide. I hope it makes sense to you.

      • Ss Shuford

        Thank you so much, that is very clear.  If we continue and do atDNA testing, would testing my DNA rather than his make a significant difference in locating matches that would help with this brick wall?  I am one generation further from the unidentified individual.  He would be my three great grandfather rather than my cousin’s two great. 

        • CeCe Moore

           @47f4f29d2a588316e65d95e4164f6f36:disqus – Yes, it could make a big difference since you are already right on the edge of where atDNA can be quite confidently used. If you decide to do atDNA testing, you should always test the individual who is most closely related to the ancestor in question. BTW, 23andMe has a sale ending in two hours. The discount code for $50 off is on my blog.

      • IsraelP

        How important is it to test how many markers? I did 67 myself, but other members of my project did only 37. Should I be upgrading them? Should I be looking at 111? Would a match there allow me to say “proof?”

  • http://www.facebook.com/people/Glenn-J-Hill/1647122326 Glenn J. Hill

    Hi CeCe I have not seen a mention in your blog of DNA-Tribes? Have you seen their results and can you offer a comment on how accurate they are ? I have had both their autosomal DNA test, and their SNP test, as well as the at tests from both Family Tree DNA and Ancestry.com. The results from all three companies are similar, though Tribes gives way more detail. So I am interested in if anyone has done a detailed comparison of the at tests, as well as looking at the SNP results form Tribes. My understanding is that Tribes uses the global data base that is used normally for individual identification purpose as in criminal investigations, in their SNP testing.

    Thanks for any insight into just how accurate Tribes testing is?

  • CeCe Moore

    I have written a post comparing the 4 major companies’ admixture results or “ethnic” breakdowns here: http://www.yourgeneticgenealogist.com/2012/12/comparing-admixture-test-results-across.html

  • Larry

    I enjoy your blog. I recently completed the Genographic 2.0 test. I have good genealogical data indicating my ancestors were English, Scottish and Irish. I was very surprised when the two closest profiles attributed to my genetic markers were German and Greek. The German made some sense to me as it could be a result of Anglo Saxon migration into Britain. However, i’m stumped as the Greek designation? Any thoughts?