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Extending Family Trees with DNA Testing

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Genealogists trace family trees through vital records and historical documents. But the paper trail eventually ends at a “brick wall.”

Non-paternity events, such as illegitimate births, adoptions, and name changes can also mean that a branch you are tracing may not, in fact, be part of your biological tree.

DNA testing can break through brick walls and find the truth. 

Amateur and professional genealogists are using it to confirm links where conventional source records do not exist or are incorrect. 

In my case, DNA helped me pierce the secrecy of adoption and discover my biological father’s family. Beyond that, the DNA results helped me track my father’s line back two more generations than previously known.

Almost as exciting, the process introduced me to many cousins with whom I share a common ancestor. So now I have a whole team working to extend our family trees.

Good News for Your Family Trees

Now you and other genealogists can learn from my experience and use DNA to accurately determine your relationship to your ancestors.

My Guide to DNA Testing

In addition to exploring this web site, I suggest you download my eBook: Guide to DNA Testing.

I describe and compare the major test types. Then I explain their purposes, strengths and limitations in a unique table that you will not find anywhere else.

This Guide provides the high level overview you need to put the various tests in perspective.

Then learn the top ten things you can do with DNA in a family tree history search. 

For an introduction to the three most important tests in genetic genealogy read my DNA Ancestry Test page.

The next thing is to clear up some common misunderstandings and get more details about the three basic tests in DNA Genealogy. 

A new type of DNA test, which can be taken by men or women, helps you find and confirm relatives from about the last five generations. To learn more read my Autosomal DNA Testing page.

Only three of these powerful new tests are available:

Now that the price of each test has dropped to less than $100, I recommend that most people take all three.

If you do need to choose just one, read my Autosomal DNA Comparison page.

Check Now to See if I Can Save You Money

As I learn about special promotions, I blog about them. You can read recent blogs on the What’s New page. Plus, you can subscribe to my blog through your RSS reader.

For general tips on saving money on DNA tests at any time see my DNA Testing Cost page.


To help you get the best return on your investment in genetic genealogy I’ve broken the process down into eight steps.

1. Choose a Test Type
2. Choose a Test Company
3. Place Your Order
4. Collect Your DNA Sample
5. Review Your Results
6. Explore Your Matches
7. Share Your Data
8. Keep Learning

For a complete explanation of these steps and the links you need to implement them, see my How to Get Started page.

My first choice for genetic genealogy tests is Family Tree DNA. To learn why I recommend this company so highly, read my FTDNA Review. 

FTDNA sponsors thousands of DNA Surname Projects run by volunteers. If you did Y-DNA testing, you can join as many as you like.

Third Party Tools

Once you have your results, you can download your raw data from the testing company web site. Various third-party sites offer tools for additional analysis of your data.

One great site for analyzing your autosomal DNA results is GEDmatch.com.

Another good site, especially for adoptees, is DNAAdoption.com.

Other Tips

Certain populations, such as Ashkenazi Jews and Low-German Mennonites are endogamous, i.e. they tend to marry within their culture and may have multiple ancestors in common. Learn how do deal with endogamy and DNA.

By the way, an excellent way to share your results with other family members (and explain them clearly to everyone) is a personalized report. 

Sometimes a person you would love to test has already died or is otherwise unavailable for testing. It may still be possible to get a useful DNA sample. See my page on Forensic DNA Testing. 

DNA Terms

Any discussion of genetics will involve some DNA terms. When I use technical terms on this site, I explain them. But you may want to look up a particular word or phrase.

The International Society of Genetic Genealogy has a Genetics Glossary.

If you would like a printed book of DNA terms, I recommend the Genetic Genealogy DNA Testing Dictionary by Charles F. Kerchner, Jr.

[NOTE: My links to other sites open in new windows. If they don’t work, check your popup blocker.]

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