More and more people are getting their results back from the DNA testing that Ancestry.com has been offering.
Some are very disappointed to downright angry. Some think it's a fraud because it doesn't agree with what they've proven.
This is going to be somewhat technical. I'm sorry for that. I hope I don't bore anyone too much.
First and foremost, in a previous blog, I talked some about the differences between our cultural and genetic ethnicity. You can read it here. It starts toward the bottom. If you read the whole post, you'll see that I didn't expect the results to solve much of anything. It's a tool, not magic. I still believe it's a tool and not a magic bullet.
Another thing I want to point out that any DNA test that is priced at a hundred bucks is not highway robbery. Honestly, it's a bargain basement price. Especially since it tests several thousand markers. It was either 70,000 or 700,000 markers. Good grief, if you think that's expensive, you have not had much lab work done. Need a blood transfusion and if we find an antibody in your screen, you'll know that it costs a lot more than 100 bucks to find out what antigen (which is a marker) that you don't have but you've developed an antibody to from a previous transfusion. That's one marker for a lot more than a 100 bucks.
Now for the science to genetic testing. I'm going to use what we know about our little red blood cells. We have a genotype and a phenotype. Some people's genotype and phenotype are exactly the same.
Red blood cells 101. As a rule, we think of four blood groups. Type O, Type A, Type B, and Type A,B.
Your blood type is your phenotype. It's what we can test and observe. It does NOT mean it's your genotype though.
Your genotype is the set of genes you carry. Your phenotype is what we can observe in the lab.
Confused? Let me give a very brief and I hope simple fact of life. You inherit one set of genes from your mother and another set of genes from your father.
Type O blood only means that it lacks the antigen associated with Type A and Type B. Type A blood has a different antigen than Type B, which is why we can observe and note with confidence your blood phenotype.
Remember, we inherit one gene from Mom and one gene from Dad.
Let's say Mom is Type A, B and Dad is Type O. What that means is our mother inherited Type A from her mother or father and Type B from her mother or father. Since your dad is Type O, it means he inherited neither the A or B antigen from either his mother or father. What will your parent's children blood group be in this scenario?
Their phenotype will be either Type A, or Type B.
Mom----------> A antigen B antigen
Dad
|
|
O antigen A,O B,O
O antigen A,O B,O
The genotype (the actual genes that you have) can only be A,O or B,O in this case. Your phenotype (what we can actually measure) will be Type A or Type B.
In my case, my phenotype is Type A. I do not know what my genotype is. It is either A,A or A,O. If I had had a child with Type B or Type O blood, I'd know that my genotype was A,O. But if my children are either Type A or Type A,B, then there's no way to know what my actual genotype is. Any Type O blood cells that I may or may not have received from one of my parents is still hiding if they exist. We can't pick them up with our testing. We can only find them when Type A and Type B are both absent.
Your blood type is one marker. Only one marker. And you see how you can believe you're one thing, yet you could be so much more than that one thing you think you are. If you're Type O, it's cut and dried. Your genotype and phenotype are the same. Ditto with Type A,B.
But I only inherited half of my genotype from my mother and half from my father. Both of them inherited a gene for their blood type from their mother and their father. I've lost half of each one of my parents traits, since each of them was only able to pass on 50% of their genes to me. My siblings got some of the ones I didn't get. And some of them went to the grave with my parents, never to be seen again in my direct blood line.
As we go back in our trees, it's becomes easy to see how many things do get lost and how something can be hidden and comes to light today that shocks us. It's always been there, but since we can only test phenotype (what can be observed) and not genotype (our actual genes) then it's easy to see when a DNA test uses 70,000 or 700,000 markers how we can all be shocked beyond belief.
If you want to learn more just type "genotype versus phenotype" into your favorite search engine. Google really is our friend. :-)
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