OK, don’t answer that.
When we’re working with our autosomal DNA and that of our close family members, we only see our immediate results.
For example, I can see that I share a total of 407.92cM segments of DNA with my second cousin, and our longest shared segment is 81.34cM.
Does that mean that another match with 407 shared segments is also a second cousin match? In other words, is 407 normal for second cousins, or an outlier, and how would I know?
When we’re trying to figure out where a match might fit in the family – and how distantly related we really are to that person, we need a broader perspective. We need to know what the average is, but we also need to know the possible range. In other words, we need a lot more data than just our own to know where the most likely placement of this person is, and where they might fall in the range. I mean, let’s face it, my family has not one time EVER fallen into the normal range of anything!
I have done a lot of cousin testing within the family, and I’ve compiled a chart of the amount of shared DNA that these various people share, along with the longest segment. Why did I do this?
Blaine Bettinger is getting ready to do the grunt work. He’s going to crunch the data and prepare the ranges for how much DNA is shared by people of various relationships – and all he needs from us is raw data.
Blaine wrote about this recently, along with super-easy instructions for how to compile and contribute your data. It’s right on your Family Finder match page – and Blaine makes submitting your information easy.
You don’t need a whole list, like mine. If there is an overachiever gene, I’m sure I have it. I have contributed my information to Blaine already – because I think this kind of a project – to be shared among all genetic genealogists, is very important and will benefit everyone. It takes very little on our part and a whole lot more work on Blaine’s part – and I’m not only very grateful – I’m more than willing to submit my data. And hey, if you submit your data before April 1st, you are eligible for a Family Finder kit from Blaine – and no – I don’t think that’s an April Fool’s joke. Maybe you’ll get a kit with no swabs:)
So, how weird am I anyway?
I sorted my spreadsheet by the total shared DNA segments and I added a column for the percentage of expected shared DNA.
You can see that this holds together quite well and just as expected through the 1st cousin/great-granddaughter range which is 12.5% expected shared DNA.
However, below that, the expected amount of DNA and the actual amount of DNA becomes shuffled or “out of order.” For example you can see that I have a second cousin once removed that I share 460cM of DNA with – and I should share 1.56% of DNA with them. Just below that row, I have a first cousin once removed with whom I share 414cM of DNA with, and who I’m supposed to share about 6.25% of DNA.
We’ve talked several times about how DNA isn’t always passed in 50% amounts, even though that is the average, and this shows the cumulative effects of this phenomenon, especially after you’re out a couple of generations.
So, now we wait. I want to know if my family falls into the middle or expected range. I want to know if my family is an outlier. Maybe, for a change, we’re normal. Nah!!! I want to know just how weird we really are.
Don’t answer that….
Just send your data to Blaine and he’ll take care of that answer for all of us.