The Genetic Genealogist

Yesterday we began to look at an email conversation I had recently with Jasia from The Creative Gene about genetic genealogy.

Jasia began by asking whether she should test both her and her mother’s mtDNA (I advised her no, because they would be the same sequence), and then we talked about testing her father’s mtDNA. Since her father could not be tested directly, Jasia wondered if her brother could provide a sample of her father’s mtDNA. I explained that although her brother could provide a sample of her father’s Y-DNA, she would have to find other sources for her father’s mtDNA, including her father’s sisters or brothers, or the children of her father’s sisters. She responded:

“Fortunately, my dad came from a large family including 6 sisters 4 of which had children. So I have cousins a plenty and can probably find one of them to help me out with a little saliva

“So is the mtDNA more valuable to the genealogist than the Y-DNA? Does it give more/different information? Would there be a benefit to having my brother’s Y-DNA tested as well as one of my paternal cousin’s mtDNA?”

With lots of sisters and cousins, it looks like Jasia won’t have any problem finding someone willing to help her out with this endeavor. She’s very lucky in this respect – in many families, the sources of DNA either don’t exist or have disappeared forever.

Her next question is also one that many people ask. Why test both mtDNA and Y-DNA? How are the results different and is either test more informational than the other? Here’s how I answered:

“I’m not sure I would say that mtDNA is more informative than Y-DNA, or vice versa. They’re just different. The result of an mtDNA test reveals your maternal lineage all the way back to a haplogroup founder. My mtDNA test, for example, revealed that my maternal lineage belongs to Haplogroup A, a Native American haplogroup. My wife’s mtDNA belongs to Haplogroup H, a European haplogroup.

“The results of a Y-DNA test will tell you much the same thing, except that Y-DNA traces the paternal lineage. The results will put the Y-DNA into a haplogroup family, and that information will tell you about the origin of the Y-DNA. One of the benefits of Y-DNA testing is that it is associated with a surname. There are many surname groups that a person can join once they have the results of their Y-DNA. The theory goes that people with the same surname are more likely to have the same Y-DNA (that is, they are more likely to be paternally related).

“So, each test will tell you something about the line that it traces, either the maternal line or the paternal line. For me, having both pieces of information was fun, mostly for the sake of knowing it and learning more about my own ancient roots.“

Jasia then suggested that I write up the correspondence as a blog post to help out all the other newbies out there. I’d like to thank her for the fun and interesting correspondence, and for the idea and permission to write about it! If you can, I suggest you go check out her site, The Creative Gene.

You can read Part I in this series here.