Just for fun, let’s look at some Crumley folks who are related. When you work in the genetic genealogy field, people are forever sending photos of someone and saying “doesn’t this person look like that person? Do you think they are related?” Or, the most common, “this is my great grandmother – do you think she looks Native American.”
I am forever telling people that phenotypical resemblances are really not good indicators of relatedness, but it’s so difficult to believe when you’re looking for that needle in the haystack and it’s the only tidbit you have.
I did it myself when I found Lee Devine and discovered that not only was he deceased, but he had no children, so my chances of ever finding out definitively if he was my half brother are forever gone. I reverted to picture comparisons, because it’s the only tool I had at my disposal.
So, let’s have some fun with this.
Take a look at this photo. These men are unquestionably related. The question is, how closely?
So, how do you think they are related?
If you said brothers, you’re in good company. They look like brothers, but they aren’t.
If you said uncle and nephews, you too would be in good company, but nada.
These are all Crumley men, left to right, John, Ken, Jerry… and Donna, the daughter of one the men whose job it was to keep them in line that day. Fortunately for Donna, she doesn’t have the signature family beard!
Years ago, the Y DNA tests through the Crumley DNA project confirmed that these men share a common Crumley ancestor, but despite appearances, they are much more distantly related than you might think.
Not first cousins.
The common ancestor of these men is John Crumley, born about 1737.
Yes, I know how much alike they look, but looks can be deceiving – or encouraging – and looks are not an accurate predictor of relatedness.
John and Ken are 4th cousins once removed.
Ken and Jerry are 5th cousins.
John and Jerry are 5th cousins once removed.
Their pedigree chart is shown below.
Not quite what you would expect by looking at the picture. As someone once said to me, “If you look at a picture long enough and hard enough, you can see anything that you want to see.” Touche!
The Crumley DNA project at Family Tree DNA has embraced autosomal DNA testing, so all three of these gentlemen have taken the Family Finder test. Knowing that their Y DNA matches (with a mutation or two), and having identified their common ancestor, let’s see if their autosomal DNA matches as well.
At Family Tree DNA, one must meet a 20 cM total DNA matching threshold, and an individual matching segment threshold of 7cM in order to be listed as a match. Here’s how they matched, or didn’t.
Needless to say, if we didn’t already have the Crumley Y DNA results, this might have given Ken a bit of heartburn – but no need. It’s not uncommon for distant cousins to not be shown as matches.
Fortunately, all three gentlemen also downloaded their results to GedMatch, where we can adjust the matching threshold. In some cases, the 20cM total precludes a match, and in some cases, the 7cM segment precludes a match, so let’s see if these gentlemen match at GedMatch using a lower threshold.
At GedMatch, I ran all 3 gentlemen against each other using the threshold of 300 SNPs and 3 cM and then put their results into a common spreadsheet. I also deleted the duplicate entries, because for every Ken to John match, there is also an identical John to Ken match.
You can see on the spreadsheet below that John and Jerry match each other, just as Family Tree DNA said. They share not one, but two large matching segments of over 16 cM. Not bad for 5th cousins once removed.
You can also see that Ken matches both Jerry and John, but not on any segment over 4.9 cM, which precludes matching at Family Tree DNA. However, Ken exceeded the 20 cM total match threshold with both Jerry, at 51 cM and John at 35.8 cM – but a match has to exceed both thresholds to be counted as such.
Especially within known family groupings, a non-match doesn’t necessarily mean the individuals don’t share any DNA, it may just mean that there isn’t enough cumulatively (>20 cM) or the segments are too small to put them over the threshold (7 cM). That’s the great thing about GedMatch, you can adjust your own thresholds.
Are all of these segments valid, meaning are they identical by descent? Most likely not. Are some valid? Very probably, especially given that we know that these men unquestionably do share a common ancestor – thanks to their Y DNA. Could we find out more? Yes, we can, if we have more cousins to compare against.
And, as luck would have it, we do, another 40 or so….but that story will have to wait until the Crumley DNA Study is ready for publication!
Thanks to Ken, Larry and John, my Crumley kin, for DNA testing and allowing us to tell their story and share their picture. You can see by the smiles on their faces that they are truly enjoying their kinship – and that is really what matters. Genealogy and genetic genealogy has the ability to reunite families separated by more than 200 years and 6 or 7 generations – and that’s exactly what has happened with our Crumley kin.
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