We Are Family!

This summer some of the members of the Topeka genealogy community did an experiment. We compared our DNA to see if we were related. What we found out might shock some people, but it didn’t shock us. We’ve been researching our family trees for some time and know that anything is possible.

Digging Into DNA Results

After receiving your DNA from any one of the companies you choose, you can download your “raw data.” That’s all the possible combinations of the letters A, C, G and T representing the four nucleotide bases of a DNA strand — adenine, cytosine, guanine, thymine — the backbone of our DNA make-up. Everyone’s has a different combination of these letters on each of the 23 chromosomes. Each of us are unique in that way.

Shared CentiMorgan (cM) Chart

Click to enlarge.

Some of us share the same combinations in different places on a chromosome. That’s called segments. Those segments can be really long or really short and are made up of what is called centiMorgans (cM). The more centiMorgans we share, the closer we’re related. This chart can help you see the relationships associated with the number of centiMorgans you share with your family.

Experiment Results

Our experiment consisted of eight people from the community who wanted to see if we were related. We each took our “raw data” and uploaded it into Gedmatch.com, a third-party software tool for DNA. It compares DNA by chromosome and by segments and creates charts showing the comparisons. Most of us had matches at the 3-5 cMs level. That shows that we have distant relatives, meaning we are all likely 6-7th cousins.

Some of us share more on multiple chromosomes. Some of our group share a total of 60 cMs. That means they are closer cousins, 4-5th cousins. Two of them didn’t even know each other before this experiment. It all goes to show, you never know where your relatives are. But you might want to learn more about your family, just to know if you might have a relative right next door (or a least in the same town) who you didn’t know.

The library has regular beginning genealogy classes. Check out our schedule for the Computerized Genealogy class.

To find out more about genealogy and DNA testing, check out these posts Got DNA Now What and What’s in Your DNA. Check out these books to learn even more.

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Sherri Camp

As a veteran genealogist, I love teaching and sharing digital family history and genealogy techniques and helping people solve genealogy problems. Being the Genealogy Librarian at the Topeka and Shawnee County Public Library is so much fun! I work to promote a greater knowledge of family, history, and heritage.