Anticipating DNA Results

So you send your sample in for testing and then you wonder what kind of results you might get.  Everyone knows that we inherit half of our DNA from our mother and half from our father.  Knowing this, it is logical that 25% of our DNA would come from each of our four grandparents.  The waters get a little muddier with siblings, aunts, uncles and cousins.  I found this great graphic on Wikipedia that helps make it clear. (All graphics can be enlarged by clicking on them).



Graphic Credit: Dimario, Wikipedia Commons

The Human Genome Project determined that humans share 99.9% of their DNA in common, although this exact percentage has recently been challenged.  This means that all of the diversity among humans comprises a relatively small part of our entire genome.  Since I'm not aware that any of my close relatives have been tested (yet) and I know most of my close relations, I really didn't expect to find any "cousins" that would fall within the second cousin category or closer -- and I didn't.  Here is what I did discover.

Unlike FamilyTreeDNA, 23andme scans all of your genome to look for patterns that may be used to predict your ancestry.  Mine turned out to be 100% European.  No surprise there.  Here are my results.

I really didn't understand this graphic until I compared it to a graphic for someone that had more of a mixed inheritance pattern.  Here is a sample for an African-American man.

I find it interesting that, as is the case with so many African-Americans, a lot of this man's ancestry is European in origin.  You can go to 23andme, create a free account and explore other sample groups under "Ancestry Painting."

When 23andme compared me to others in their database, the closest relationship they could identify for me was a potential 4th cousin. You can see from the table posted above that I would not anticipate sharing much of my DNA with this person.  23andme computed that we shared 0.48% of our DNA -- big whoop!!! (Note:  I've since found out that the 36 cM we share is a big deal.  Who knew).  Here is what we share in common.

You are reading it correctly.  We share one little section on chromosome 20.  I'll bet I share that much with my husband.  I guess I'm going to have to have him submit a sample.  So come on, cousins, submit a sample!  I want to have some fun.

In my next post, I'll discuss what I found out from a medical point of view.