DNA doesn't lie, you just need to understand the science

Source:  DNA doesn't lie, you just need to understand the science    Tag:  tetragametic chimerism
For the past several days I have struggled with whether or not I was going to publish this post.  After talking with several friends, and watching others I know become confused over the science, the decision was made for me.  I think it is time for a lesson in genetics on how it can or can’t affect us.

On 14 June 2014 there was a blog post by Michael J. Leclerc about a genetic condition that can occur in humans.  To say it caused undue stress, hand-wringing, and confusion is an understatement.  Just read the comments and the comments on the re-posts of the article.  The title, unfortunately, may be part of the problem, I mean can DNA lie to you?  You see DNA doesn't lie but it sure as heck can be misinterpreted if it is not read by a person who completely understands what they are looking at. 

Image from the Library of Congress

The people he talks about in the post are Chimeras.  No, they are not the creatures from mythology, but something that a lot of non-geneticists struggle to understand.  Essentially being a Chimera means that one person has 2 sets of DNA in their body.  For example, the stomach may be genetically different than the skin.  It seems fantastical, but yet, it does happen.  In fact, many doctors believe that it may happen more often than people realize. 

I won’t bore you here with a lot of the technical information.  Trust me I could go on for pages about the types of Chimeras, how they forms, why they forms, and how many of them have absolutely no idea.  Instead there is a list at the end of this post for further reading.  If you are really interested, please go read up on it.

What I will do is explain how being a chimera will have absolutely no impact on your genealogy testing.  OK, let that sink in a second.  This condition will NOT affect your genealogy. 

Some of you may be shaking your heads, trying to understand how having 2 sets of DNA won’t throw something for a loop.  Simply put, you are the product of you parents.  All of the DNA within your body came from 2 cells: an egg and a sperm.  ALL OF THE DNA.  This means, for genealogy purposes you can still take genetic genealogy tests if you are a Chimera because even though you have more than one set of DNA it all came from the same 2 people.  

Since I am trying to not go really in depth with the science in this post I am going to leave that here for now.  If you are really intrigued, please contact me or leave me a message and I will go into further detailed explanations.

Which Half is Mommy? Tetragametic Chimerism and Trans-Subjectivity (long journal article about the 2 women in question, the medical history, and the societal understanding of the phenomena)