DNA testing tips: getting the most out of your genetic genealogy

photograph of tree in early spring

DNA Day is here and many have been snapping up DNA test kits on sale this week at FamilyTreeDNA and Ancestry.

Most probably test because they want to learn what the test will tell about their ethnic makeup. But for serious genealogists and family historians, testing opens the doors to exciting yet often bewildering territory.

Here are my top three tips for getting the most out of testing your autosomal DNA:

  • Tip 1  Once your results are in, upload your raw data to Gedmatch.
    Gedmatch is a site that provides free DNA analysis tools and allows one
    to match with others across four major testing companies.
  • Tip 2  Test others in your family, starting with the oldest members.
  • Tip 3 Make concrete goals rather than end goals for exploring your genetic genealogy.

When I first took the DNA plunge and entered the confusing new realm of genetic genealogical research, I felt a bit had.

But I’ve learned a lot over the past year. And I’m beginning to reap something of value from a bit of swabbed saliva and inner cheek tissue.

I quickly realized that in order to reap more reward from my foray into genetic genealogy, I needed to do two things:  revise my goals and test others in my family.

My original goals consisted of vague hopes to connect with matches in the second to third cousin range on my Jewish and Irish lines. However, I soon discovered that endogamy makes this a Herculean task.

Instead, I decided to focus my efforts on my one of my nearest brick wall ancestors. By doing this I not only had a concrete goal, but was also able to formulate a genetic genealogy plan o’ action.

My brick wall ancestor, Sarah E. Brown, is my third great-grandmother on my paternal grandmother’s branch of my family tree, through her mother’s side. Her maiden name is unknown, as are her origins. As many researchers well know, locating 19th century records in central Pennsylvania is often impossible. For Sarah, the paper trail has been cold for two decades.

So, I am turning to DNA testing in hopes of locating other descendants of her family line.

Experts strongly recommend testing the oldest generation of one’s family for good reason. We inherit exactly half our autosomal DNA from each parent, but each successive generation passes on just half of that half.  Simply put, the oldest generation carries significantly more of one’s ancestors’ DNA. (For a more in-depth explanation, please read Roberta Estes’ excellent article on the subject.)

Unfortunately, my Dad and Grandmom died years ago. This meant I needed to find other older family members who would be willing to test.

Right away, I was able to recruit my Aunt Lisa (my Dad’s only sibling and the oldest living member of his side of the family).  That helped me figure out better which matches came from my paternal line.

A few months later, my Grandmom’s first cousin through her maternal side, Shirley, also agreed to test. Her DNA test has proved to be of enormous value.

Testing two other family members has enabled me to triangulate the matches we have in common. In a short time, this has led to a few connections with more distant (second and third) cousins that have been further verified through good old-fashioned paper trail genealogical research. It also led to one heck of a discovery.

Through those matches, I am slowly figuring out which triangulated segments relate to particular branches of our family.

My great-grandmother, Lulu (née Reuter) Bender, just happened to be the eldest daughter in a tight-knit family of 14 children. I am very fortunate that some of my Grandmom’s youngest cousins are still living.

This week, two more of her maternal first cousins – Patti and Lowell – have decided to test.

We all share some DNA passed down from my grandmother’s maternal grandparents: her grandfather was of 100 percent German ancestry from mid-19th century Catholic immigrants. Her grandmother was half Pennsylvania-Dutch (so again, German… only Protestant and dating back to colonial America).

The other half is the mystery we are all trying to solve.

Initially, I thought Patti’s mother was of 100 percent Italian ancestry and got excited thinking that if she tested and had any matches that were not of German or Italian ancestry, then it would be easy to identify which matches connect to our brick wall ancestor.

However, her mother turned out to be half Irish descent… so it turns out each cousin’s non-Reuter parent and my own great-grandfather all have British Isles ancestry.

Identifying matches descended from our shared mystery ancestor will be more challenging than I hoped. But through triangulating all three cousins, plus my aunt and myself AND then seeing if those matches triangulate (or not) with the verified distant cousins on the Pennsylvania-Dutch and German branches – maybe we can figure out the probable connections to Sarah.

Because even if she is of British ancestry, as I suspect, my thinking is that it is unlikely that any of us will share matches in the second to fifth cousin range who are of British Isles descent (unless endogamy again comes into play, which I suppose is possible).

What might prove quite useful is a comparison of X chromosome matches. Since Lowell is male, he only inherited an X chromosome from his mother, who was my great-grandmother’s youngest sister. Being female, Patti will have inherited her X chromosomes from both parents. However, Patti ‘s father was my great-grandmother’s brother – so if her X chromosome matches triangulate with Lowell’s (and the rest of us), those matches will assuredly be from our Brown line as her father would have only inherited the X chromosome from his mother.

I can hardly wait for the test results to come in…

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