Ten DNA Sleuthing Tips

In my recent webinar, The Second Middle Passage: Following the DNA Trails, I used colorful diagrams to show genetic groups. Each genetic group contains DNA matches who descend from the same ancestor or ancestral couple. I researched their common ancestors to determine how they could be related to mine, and thus justifying why some of their descendants are sharing noticeable amounts of DNA (at least 20 cM) with my mother or father.

While some DNA relatives attached family trees to their profiles in AncestryDNA, MyHeritage, or Family Tree DNA, some of them did not have family trees at all. Many will not. Do not fret; there are ways to try to unearth more information. Also, several DNA matches in the genetic groups took the 23andMe test; hence, no family trees were available. Here are ten tips on how I captured family info, built out family trees to find the link, and found good clues.

TIP #1 – Work with what you see, if possible. Even if someone’s tree has few names, and many do, it might still be a good starting point. If I do not recognize the names and surnames on their scant trees, I look at where their ancestors lived for clues. If there is a familiar location (county/state), I typically investigate that side of their tree first. I research their ancestors in Ancestry.com, FamilySearch.org, and other sites as if I am researching my own. I have a genealogy notebook where I sketch out their pedigrees. Also, electronic pedigree charts can be used. Here’s a good downloadable one that uses Microsoft Excel.

TIP #2 – Pay attention to similar ancestors. In some cases, after building out a match’s family tree further to find the connection or a clue, I did not initially see anything I thought was noteworthy. As I explored the available family trees of some of the other shared DNA matches, I discovered a familiar ancestor that I had uncovered in another match’s family tree. That helped me to pinpoint the common ancestor between multiple shared DNA matches. I then focused my research on their common ancestor.

I am especially happy when multiple shared DNA matches descend from two or more children of their common ancestor. This gives me an extra layer of confidence that I have positively identified their linking common ancestor, and somehow, he or she was related to one of my ancestors, provided that those shared DNA matches do not share other lineages. This lends itself to tip #3.

TIP #3 – Look for other possibilities. If two or more shared DNA matches appear to descend from multiple common ancestors, I investigate those lines, too. However, I have been lucky thus far that most appear to descend from one common ancestor or couple. This may not be the case in areas where lots of intermarrying occurred, or if a shared DNA match’s maternal and paternal family remained in the same area for generations, resulting in numerous “double cousins” or endogamy. This situation makes determining the link even harder, but other shared DNA matches, with DNA triangulation if possible, might help to narrow it down.

TIP #4 – Use social media. I have had success with this strategy several times, and it calls for detective work on social media. A DNA match in 23andMe provided her location on her profile. Fortunately, her first and last names weren’t excruciatingly common. I searched Facebook to see if she had a page. I found her page because her name, location, and one of her FB profile pictures matched her 23andMe profile. While looking at her public pictures and reading the comments underneath, I fortunately ascertained both her father and mother’s names. I searched her father’s name in Ancestry.com and found her parents’ marriage record, which revealed her mother’s maiden name. I then researched her family until I found the link, which was on her mother’s side!

TIP #5 – Use Family Facebook groups. If a DNA match appears to be related closer than third cousins but do not have a family tree, I have taken snapshots of their profiles and posted it in one of my private family groups to see if anyone knows them. Several branches of my family have active group pages. Just recently, my second cousin identified a new DNA match as being his son, who shares 224 cM with my mother and 129 cM with me. Periodically, a family member in the group may know the DNA match and can explain the family connection.

TIP #6 – Perform Google searches. This tip addresses when I couldn’t find a Facebook page. I googled a 23andMe match’s name and found her in her sister’s online obituary. I was confident I had the correct person because her location was the same as the one noted in the obituary. Fortunately, the obituary contained lots of great family information. I researched her family in Ancestry.com and quickly found the connection. Google searches can often lead to great information or resources like obituaries. I have also searched a DNA match’s name in Ancestry.com and luckily found it in an informative obituary. The Newspapers.com Obituary Index on Ancestry can be searched here. The U.S. Obituary Collection on Ancestry can be searched here.

TIP #7 – Send the treeless DNA relative a message. When tips #4 and #6 did not yield any fruitful results, I messaged the DNA relative. I typically disclose in my first message the name and location(s) of my ancestor who I believe is our link. If I am asking them to provide me with names and locations, at least I can start by giving them some names and locations of my family. This strategy has worked periodically. Although most people do not divulge a great amount of details initially, some people have given me enough information to begin researching their family to find the link. I let them know if I made the connection. Unfortunately, many people will not respond at all, or they might respond weeks or months later or even a year later.

TIP #8 – Try LinkedIn. I’m not kidding! This may seem a little “stalk-ish,” but it worked. A 23andMe match did not respond to my message. She included a picture on her profile. I was unsuccessful with Google searches and finding a Facebook page. Tip #5 yielded no results. However, I found her on LinkedIn, a site that is primarily for professional purposes. I really desired to communicate with her because she shares 157, 172, and 175 cM with my mother, aunt, and uncle, respectively, and 137 cM with their second cousin. So she appears to be another descendant of my mother’s great-grandparents. After she accepted my LinkedIn request to connect, I messaged her. Surprisingly, she did not recognize my family names and locations, and I was not familiar with the names she provided. Despite being unsuccessful, I was successful in communicating with her.

TIP #9 – Use diagrams or charts. Once I determine that multiple shared DNA matches descend from a common ancestor, I personally like to build a diagram in Microsoft Word (Smart Art tool) to show how each descends from that ancestor or couple. I do this for record-keeping purposes, and it is a great visual aid. It also keeps me organized and helps me to build my case for those situations where autosomal DNA is revealing unknown connections from slavery. Other programs and methods are available for this purpose, such as lucidcharts.com. Also, check out the “Create a DNA Leeds Methods Chart” video or read about the McGuire Method to visually show DNA comparisons. To add, Ancestry.com has filtering and grouping options to help organize your DNA matches. Read more here.

This example is a diagram of seven descendants of a man named Henderson Herron, who had been enslaved in and resided in Tallahatchie County, Mississippi after Emancipation. My mother, aunt, and/or uncle share noticeable amounts of DNA with his descendants from four of his children. (Note: In my personal files, I include their real names.) My blog post, Genetic Genealogy Rebuilds Dismantled Enslaved Family, discusses how I discovered that Henderson and my mother’s great-great-grandmother, Margaret “Peggy” Milam of Tate County, Mississippi, were full siblings.

TIP #10 – Familiarize yourself with DNA amounts and relationships. Examine the genetic relationship possibilities indicated by the amount of DNA (cM) you or your parent(s) shares with a DNA relative. How much DNA do first and second cousins share on average? Third cousins? Fourth cousins? Relationship possibilities can be found on ISOGG’s site or from the Shared cM Project 4.0 tool. This helps to build several theories about how the common ancestor of a genetic group might be related to your ancestor. Research to prove or disprove those theories.

CONCLUSION: Major clues are often in your DNA matches. The foundation of genetic genealogy is your DNA relative database. Be patient, diligent, and determined. Don’t let frustration make you give up. Also, keeping your DNA findings organized helps enormously with your research. DNA sleuthing is not easy and can be time-consuming, but the end results can be profoundly beneficial.

6 thoughts on “Ten DNA Sleuthing Tips

  1. Melvin, this is a fantastic post that is really going to provide researchers with solid strategies to use to try to identify DNA match ancestors. I am hoping in the future to be able to connect some enslaved ancestors as you have done so very well. This solidifies why you are the first person I contact when I have a DNA question! I’ll be one of the ones waiting on your DNA book…..hint hint;)

    Liked by 1 person

  2. Barnetta McGhee White

    Great tips! Wish I understood half of them! I am a late arrival to using DNA for making connections to common ancestors. My major work was done in the 1980s when the original records was all that you had. Now, if only a few of those would take a deep breath and go along with DNA in 23andMe or Ancestry (both have my own) I could go much farther than I have. Suggestions?


    1. One way I have encouraged other family members to test is by showing what I have been able to uncover, and I discuss DNA matches and findings in my family groups. This has inspired others to test.


      1. S. Juain Young

        Hello Mr. Melvin Collier…. Im excited about your research and did get a chance to speak with cousin Joel Miller before he passed. He is also my relative and went to school with my mom in Augusta. I’m connected through Aunt Sarah and Grandpa Mason Roddy.
        I would love to speak with you and continue connecting the dots. We have other family history that may interest you.

        Liked by 1 person

  3. Hi, Melvin. I really enjoyed your post and I know it can help many people figure out who their DNA matches are and how they’re related.

    I really like the idea of a genealogy notebook where you sketch these trees. I often use scraps of paper, but I can’t revisit them! So, I think I’ll try a notebook.

    And, though I’ve heard of creating private family Facebook groups, I haven’t tried that yet. (I need to!) I really like your idea of posting about an unidentified match and getting help from your family.

    Great tips!

    Liked by 1 person

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