Saturday, June 23, 2012

“I don’t know nothin’ ‘bout understandin’ no DNA" - Autosomal DNA

When it comes to DNA, many of you, like me, might be scratching your head and saying (to paraphrase Prissie in Gone with the Wind), “I don’t know nothin’ ‘bout understandin’ no DNA.”  Boy, do I wish I would have taken time out from doodling and playing cootie catcher to listen to at least a couple of my science teachers. 

The University of Utah has put together four short little videos explaining the four kinds of DNA – Autosomal DNA, X Chromosome DNA, Y Chromosome DNA, and Mitochondrial DNA.  Currently, three of these types of DNA - Autosomal, YDNA and mtDNA (mitochondrial) are being used for genealogical purposes. 

The type of DNA that Ancestry used to predict my genetic ethnicity is autosomal.  If you are interested in understanding autosomal (a whole lot had better than yours truly could hope to explain) take a peak now at U of U’s autosomal DNA video.  

In a nutshell, each of us has 23 pairs of chromosomes.  Autosomal DNA looks at 22 of these pairs (the 23rd pair is the XY or XX chromosomes that determine a person’s sex.) 

You have inherited ½ your father’s autosomal chromosomes and ½ of your mother’s autosomal chromosomes.  But that also means that you lost half of each of your parents’ autosomal chromosomes. Likewise, your parents only inherited ½ of their parents’ autosomal chromosome etc.   

This is why your siblings’ genetic ethnicity might not look precisely the same as yours – they might have inherited different chunks of your parents’ DNA.  It’s also, why you and a cousin can take the test and not come up a match, yet you and a fourth cousin are.  It’s all in how the chromosomes recombined.

If you read the paper, “Melungeons, A Multi-Ethnic Population by Roberta J Estes, Jack H. Goins, Penny Ferguson and Janet Lewis Crain, you will see that the prediction of how much of the DNA I probably carry from my 4th great grandparents, Nimrod and Frances Thacker, is less than 1%.  If you factor in the probability that the individual who supplied the mixed race part of their DNA could have been 50, 100 or 200 years prior to their births – well, you can see why my autosomal DNA might not have picked it up.

For some of you who are descendants of the Vinton County Group, you may have expanded your chances by having several sets of the original group members.  Only testing will tell.  

Autosomal testing by should be available to the US market some time later this year.  Family Tree DNA offers their own product called Family Finder and 23 and Me calls their product Relative Finder.

Note:  As of right now, Ancestry does not offer the option of looking at raw data, which the other products do.  

Monday, June 18, 2012

Good News, Bad News - The Results of My Ancestry Autosomal DNA Test

Okay, so the good news is I received the results from Ancestry's autosomal test.  The bad news is my results don't give us a clue to the Thacker clan's mixed racial identity.

I made a prediction of my own on what the results would look like. I predicted 73% Central European (I have German ancestors all over the place), 25% British Isles, and 2% Uncertain.

Below are the actual results.

So the thing is, I don't have a lick of Scandinavian heritage (Norway, Denmark and Sweden) in my family tree.   Ancestry, however explains it this way: 

For example, if you have German or British ancestors in your family tree, it’s a possibility that your genetic ethnicity may be partly Scandinavian. The Viking invasions and conquests about a thousand years ago are likely responsible for occurrences of Scandinavian ethnicity throughout other regions.

Okay, I can accept that. In addition, a quarter of my family tree came directly from the former German Province of Pomerania.  A portion of this province, known as the Hinterpommern, was in fact part of Sweden from 1630 to 1815.  This happens to be the exact area where this part of my family tree lived.

The Southern European is a bit of puzzler, however.  This area encompasses  Spain, Italy and Portugal.  I swear that I have not found one incidence of any of this ethnicity in my family tree.  It is interesting to note that many of the Melungeon's, (no, we are not Melungeons) a significant portion of whom trace their roots to Louisa County, have claimed that they descend from Portuguese sailors. 

A recent paper appearing in The Journal of Genetic Genealogy entitled, "Melungeons, A Multi-Ethnic Population" disputes this notion of a Portuguese heritage. The paper, co-written by Roberta J. Estes, Jack H. Goins, Penny Ferguson, and Janet Lewis Crain, is based on the testing of descendents of the Core Melungeon group.  They used YDNA tests (father to son) and mtDNA tests (mother to daughter ) to base their conclusions.  The findings of these test showed mostly a Northern European heritage with some African American origins and one Native American (the Sizemore's, who were NOT from Louisa County).

Still, these odd ball results of mine are food for thought.

I would be interested in hearing about the DNA results of anyone else who descends from the Nappers, Dortons and Thackers.  If you have had any testing done, please share.  You can either leave a comment or you can write me at the email address found on the left hand column of this page.  Maybe together, we can solve some of the mysteries surrounding The Vinton County Group.

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