Heteroplasmies and Poly-Cytosine Stretches – An mtDNA Case Study

I don’t match my mother’s mtDNA test results.

How is that possible?

Last fall during the sales at Family Tree DNA, I ordered an mtDNA test for my mother. Now, usually there isn’t a need to test your mother’s mtDNA if you’ve tested your own, and vice versa. You should have the same mtDNA results, and in almost all cases you will.

However, I decided to test my mother because I have a mutation that puts me at an mtDNA genetic distance of 1 relative to matches that are likely related about 200 years ago in the Caymans where my mtDNA came from. That mutation always bugged me. Although it certainly isn’t unusual to have a GD=1 at 200 years, my maternal line is a work in progress so I want as much information as possible. So I decided to “walk back” the mtDNA line as far as I could. Although my mother was only one generation further back, it couldn’t hurt to have her mtDNA sequenced just in case it could shed light on this mutation (and, frankly, the sale was too good to pass up!). ... Click to read more!