DNA Testing for Genealogy – Getting Started, Part Four

Posted August 8, 2012 by Geni | 26 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.


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.