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HVR1 Mutations and the Cambridge Reference Sequence
When genealogists do mtDNA research, they are looking to see where they fall in the worldwide research of mtDNA, and how they match up against other relatives.
The HVR-1 region of the mitochondrial DNA is a defined region that has been well studied. Scientists have developed the Cambridge Reference Sequence which is the "master template" of what that region should look like. Of course, over the thousands of years, tiny mutations have occurred. Scientists have tracked those mutations over time to see where the various groups of people ended up.
When you get a mtDNA genealogy test done, one of the things you are told is your HVR-1 mutations. For example in my test, I was told my father's maternal ancestry was:
HVR1 Haplogroup: T
HVR1 Mutations: 16126C, 16294T, 16296T, 16519C
Note for those with privacy concerns, the HVR1 region of your mitochondria doesn't "do" anything like determine your eye color or hair color or such. It is just a tracking area that is perfect for seeing how generations are related to each other.
The person we were testing again, Presley, had these results:
HVR1 Haplogroup: T
HVR1 Mutations: 16126C, 16294T, 16296T, 16519C
In essence the four mutations say things like "In spot 16126 I was expecting to see a C instead of what I saw" and "in spot 16294 I was expecting to find a T instead of what I found". It is highlighting the things different from the reference chart.
So looking at this, we have a perfect match! You might think it meant the two were cousins. But really, haplogroup T is a giant group of "people from England". Haplogroups are extremely broad designations. The match of four mutations does means that the two men have a common female ancestor - but it could be as far back as 1,000 years ago.
Luckily, most DNA Testing agencies offer a second set of tests on another region of mitochondrial DNA, the HVR2 region. That way if both the HVR1 *and* the HVR2 match, you know you have a relatively recent common female ancestor.
OK, so I started looking at the HVR2 region. There are literally 500 letters here in long chains like
CGTCTGGGGG
and each one of course stands for an actual part of the mtDNA chain. Very cool! So I went through the letters one by one, comparing my father's DNA with Presley's DNA. In the end, they both matched up exactly!!
This really makes it extremely likely that our two family lines intersect at the point we were researching, and that we are in fact Lumbee Indians connecting through a woman named Naomi Oxendine. We never could have "proven" that otherwise, since we have pretty much exhausted all records that exist. Further DNA testing will be able to reinforce this too, either doing the same two people with different testing firms, or doing other people as well to prove they match our DNA samples.
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Note - Lisa Shea wrote this content for the genealogy site at BellaOnline.com - you might still find this content there as well. That's fine :) I gave permission!
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