At Christmas, normal women ask their husbands for jewelry.
I asked mine for a DNA test.
It’s from a company called 23andMe. They send you a test kit…you fill a test tube with spit and mail it back to them…and in 6 weeks they give you access to their online database. You can cruise around your chromosomes and explore commonalities between your DNA and the thousands of other people who have undergone genotyping with them. In addition to their commercial enterprise, they have scientists on staff who are looking for genetic markers for Parkinson’s and other diseases.
I wanted to do the test for a couple reasons: first, I want to know if I have a genetic predisposition for any diseases. If lifestyle modifications can be helpful, then I want to make them now. More on that in a future post.
The second reason was to delve a little deeper into my family history. I’ve had the good fortune to know my grandparents and great-grandparents, and the things they’ve told me have taken me a long way along the branches of our tree. But that’s mainly been on dad’s side. That’s where grandparents have been the longest-lived. My mom never knew any of her grandparents, and we lost critical information when their generation passed on.
One of the great things about genetic testing is learning about mitochondrial DNA…genetic information that you receive solely from your mother. Whether you’re a man or a woman, every snippet of mitochondrial DNA currently in your body first resided in the egg that was fertilized when you were created. Your dad contributed none of it. (He only contributed DNA to your chromosomes, which reside in the cell nucleus, not the mitochondria).
By testing your mitochondrial DNA (mtDNA) you can learn about your purely matrilineal heritage. For people of Northern European descent, this is really interesting because mtDNA tells the story of how different ethnic groups wound up in different regions. Here’s how it went down: 25,000 years ago during the last ice age, the glaciers advanced southward and covered the European continent clear down to Italy. The only habitable regions were the Mediterranean fringe. Paleolithic people migrated southward out of Europe to escape the advancing glaciation.
As the ice age lifted and the glaciers receded, people began repopulating Europe. As women moved northward and had children, their mitochondrial DNA traveled northward too. Here’s the critical part: mutations that spontaneously occur in DNA get passed on when people have kids. That’s how genetic diseases occur, but most of the time the mutations are harmless. Harmless mutations in mitochondrial DNA began to appear in these nomadic Ice Age women. As these women traveled further and further afield, these mutations became localized to certain regions and/or tribes. The more isolated the tribe, the less intermixing with other tribes and the more homogenous their tribal mtDNA became.
Certain mtDNA types (“haplogroups”) became characteristic of Scandinavia, Central Europe, the British Isles, the Alps, the Mediterranean, etc. This was all modified by how many surviving children each woman had. If she had no surviving children, then her mutation could die out. (That probably happened a lot. Remember my friend Otzi the Iceman? They sequenced his mtDNA and though it’s broadly related to other European groups, his specific mutation has never been seen before. Apparently he has no living maternal relatives.) If a woman was fortunate enough to have children to survive to become parents of their own, her DNA would be passed on down her line. The more descendants, the more prevalent her DNA would become in her geographical region. Nowadays, scientists can sample mtDNA from indigenous Europeans and create a gene map that corresponds to migrations of people groups in the past. The same thing can be done for Y-chromosomes, which men pass along solely to their sons.
Iceland is a great example of what can be learned from genetic genealogy. We know from Iceland’s native folk tales (the sagas) that Norwegians began settling the island in the year 874. The sagas say that large numbers of Irish slaves were brought along…many of these were women who were essentially concubines. The present-day mtDNA representation in Iceland has a large Scandinavian element contributed by the Norwegian women who accompanied their husbands…but there’s a considerable element of British mtDNA too, far higher than other Scandinavian countries. The legacy of those captive Irish women is still apparent in their descendants. As we might expect, there’s no major contribution of British Y-chromosome DNA in Iceland. In a patriarchial society, Irish male slaves would have far fewer opportunities to have kids than Irish female slaves. The slave-owning Norwegian male would see to that. But that’s an example of how genetic genealogy can dovetail with historic events. Outside of Iceland, archaeologists use mtDNA and Y chromosome information in conjuction with archaeologic and linguistic evidence to reconstruct the migrations of ancient Europeans.
Back to the present day: from my pen-and-paper genealogy research, I know that I’m a total Western European mutt. Based on names and dates alone, I know that I have roots in the following countries: England, Scotland, Germany, France, Holland, Belgium, and Switzerland. I hoped that by checking out my mtDNA I might learn from which region my ultimate maternal ancestor hailed. I suspected I’d fall into one of the common groups from the British Isles or France, based on what little we know about Mom’s side.
I eagerly logged on to access my data and went right to the mtDNA results: drumroll please…I am from haplogroup X2b. Hooray…the crowd goes wild. My results were displayed as a map, with darker colors indicating higher geographic incidence of X2b. I thought “OK…English Channel, here we come.”
And then, this:
I couldn’t believe my eyes. X2b is mainly found in Native Americans? Am I… am I… ethnic?
Knowing that mtDNA is only part of the picture, I looked up the summary for all my other genetic information…the 23 chromosomes that came from all my other ancestors. And behold:
Honky, thy name is Shauna.
All my other DNA comes strictly from European sources. Native Americans would generally have about 83% Asian DNA (from Ice Age Siberians who crossed the Bering Strait) with a little bit of European (from Central Asians who were in the mix with the Siberians).
So here’s how I interpret things. Yes, I’m from a mtDNA lineage that pops up most frequently in Native American groups, especially the Algonquin tribes. But all my other DNA segments come strictly from Europeans. X2b is very rare in Europe (less than 5% of the population), but it seems likely that I just happen to be from that small group. It’s far less likely, based on my chromosomal DNA, that I have any Native American ancestry.
So back to the pen and paper genealogy. My mom’s mom’s mom was named Della Mae Thompson. Her mom was Virginia Clementine Porter. Her mom was Mary Ann…but I don’t know her maiden name. I have a census record for her from 1870 in Clay County, IL. Her birthplace is listed as Indiana. I’ve searched the internet every way I know how, but I can’t find any more information about her than that.
Porter is a run of the mill English name. It’s an occupational name. A porter could either mean a doorkeeper or someone who lugged heavy things around for a living. But it’s not really Porter information that I need. I need to find this mysterious Mary Ann’s maiden name. Record keeping was atrocious during the pioneer days…finding a paper trail is going to be tough. But if I could track her family back to the east coast, where records are more intact, then maybe I could track the line back to Europe. And then maybe I could get a better idea of where my ultimate maternal ancestor is from. But that’s a long shot. X2b is very rare, but it’s also widespread…it’s not just confined to one geographic region. It pops up at a low frequency all over Europe. Whatever Ice Age woman had the X2b mutation, her daughters spread out all over the continent. Maybe they were flight attendants.
X2b is so rare, in fact, that out of the thousands of people participating in the 23andMe database, only 6 other people besides me fall into this haplogroup.
I could add several more to their count: my sibs, my mom, her sibs, and my 6 cousins on that side that descend from aunts (not from uncle L). Oh, and the kids of those female cousins. We could get together for a little X2b convention.
So as I mentioned at the top…I’ve learned many more things from my genome, which I’ll share as I have time to write. But mom, you were right all along. You’re from rareified stock, indeed.
-shauna-
