My uncle once told me that when you assume things, you make an ass/u/me.

In the genealogy world, evidence is everything. And yet, being human, we like to draw conclusions based on the limited evidence we have. Sometimes our hunches can be right, and can draw us to find the evidence that confirms our hunch, but sometimes our hunch can be very wrong and lead us away from finding that evidence.

I have a bunch of matches on a spot on Chromosome 10 that I’ve been trying to figure out for the longest time. I made a bunch of assumptions that were wrong, based on my limited evidence, and I’ve been on a wild goose chase.

Wrong assumption #1:

These are not matches to my great-aunt, therefore they are matches on my other maternal side. WRONG. My grandfather inherited slightly different DNA from his parents than did his sister. Therefore, I have DNA from that side of the family that my great-aunt does not.

Wrong assumption #2:

These matches include a known match, F.G., and since this is not a match to my great-aunt, F.G. must be related to me in another way. WRONG. As in wrong assumption #1, I clearly have some DNA that my great-aunt didn’t get, and F. G. has that DNA as well.

Wrong assumption #3:

These matches are from all over the place: Canada, the US and even New Zealand. This does not fit with my known ancestors, so it must be from the branch of my family tree that is unknown (my mother’s mother’s side). WRONG. My ancestors in Scotland likely ended up around the world. The further back I go, the less I know about my ancestor’s siblings who may have ended up anywhere.

So here I was trying to connect my mother’s mother’s family tree up to F.G.’s maternal family tree, trying to fill out more of my mother’s mother’s family tree and banging my head against a brick wall. No matter how hard I worked to figure this out, I wasn’t going to be able to because I was trying to find a connection that didn’t exist, in a family tree where our common ancestor is not going to be found.

Here’s how I figured out my mistake. I wrote about using RootsFinder in a previous post. While fooling around with the cluster graph, I happened to notice that some of these matches for Chromosome 10 were in the cluster I had identified as being related to me through my HBC ancestors. Here’s a picture of the cluster. F.G. is in that cluster, as is my aunt, S.R.

This cluster tell me two things.

First, this cluster is not connected to any of my other clusters, which means that all the people in this cluster are related to me in only one way. (edit: I have made another wrong assumption! Thank you reader who pointed that out!). While it is possible that the people in this cluster are related to each other in a way that I can’t see because I don’t have those genes, if my chromosome 10 connection to F.G. was from a different part of my family, there would be two clusters, with F.G. connected to both my chromsome 10 cluster and my HBC ancestor cluster.

Second, while great-aunt does not share that particular bit of DNA on Chromosome 10 with these other matches, clearly we are all connected to each other on that branch of the family tree.

My next step is to identify everyone in the cluster. Since it’s a ways back, and some of my matches have very endogamous Scottish trees, it still might take some time to figure out who our common ancestor was, but at least now I’m on the right track.