Chimera DNA Is Not Why You Aren’t Matching a Parent or Child; DNA Saturdays August 17, 2019

I covered this a while back December 2018, DNA and Chimera. People don’t bother to read the articles or they don’t dig deep enough. If you are not matching at a fairly close level (aunt/uncle, niece/nephew, or a similar percentage range) after taking a major genealogical DNA test – 23andMe, AncestryDNA, FamilyTree DNA (FTDNA), MyHeritageDNA,  or a test that looks at several hundred thousand or more SNPs, it’s not a chimera DNA issue – see quote below for chimera DNA.

Adding a few more links – https://www.buzzfeednews.com/article/danvergano/failed-paternity-test-vanished-twinthis man failed several paternity tests when he was in fact the father. Those paternity tests looked at a small number of markers. Once he did a 23andMe kit, it showed him as uncle (roughly 25% shared DNA). He was the father, but the DNA in his sperm was mostly that of the chimera brother he absorbed in their mother’s womb.

https://www.sciencealert.com/it-s-possible-for-one-person-to-have-two-different-sets-of-dna-here-s-how-it-happens

I bring this up because I continually see people claiming chimera DNA is why a person doesn’t match a parent or child. If they are showing no or very little DNA in common with somebody who is supposed to be parent/child using one of the major genealogical DNA tests, it’s not chimera DNA.

To quote part of my earlier post:

Important NOTE: paternity/parent DNA testing tends to look at only a handful of markers, usually anywhere from 13 to 26, possibly as many as 200 – 400 markers or so. In comparison, genealogical DNA testing by 23andMe, AncestryDNA, FamilyTree DNA (FTDNA), FindMyPastDNA, LivingDNA, MyHeritageDNA tends to look at between 100,000ish to around 1,000,000 or so, with an average of around 500,000 – 800,000 markers. End result – you are going to significant differences between a paternity/parent DNA test than you will get with a genealogical DNA test.

One of the most common explanations by non-experts for a DNA mismatch is Chimera or Chimerismhttps://en.wikipedia.org/wiki/Chimera_(genetics) although a better article might be https://www.thisisinsider.com/what-is-a-human-chimera-and-how-does-it-happen-2017-11, or https://www.scientificamerican.com/article/3-human-chimeras-that-already-exist/.  Exactly how common chimeras are is up for debate: https://bigthink.com/robby-berman/you-could-be-your-own-twin. I don’t think it’s anywhere near as common as some articles indicate, but it’s the leading answer by non-experts if you and a DNA match don’t match. I first became aware of the term through a CSI episode (2004) – https://www.imdb.com/title/tt0534653/ (NOTE: it’s an episode involving rape) long before I submitted my first DNA sample. I have yet to come across any reliable estimates on how common or uncommon the condition is supposed to be. This is different than chimera DNA resulting from bone marrow donation or the mother absorbing some of the child’s DNA during pregnancy. In the first case, your DNA may show as the DNA from your bone marrow donor or a mix of your DNA and the donor’s DNA. If it’s a close family member, then the chimera DNA would show as being related, but not necessarily as close as you expect. In the second case, it’s usually trace amounts of shared DNA although it should indicate a relationship.

–snip–

Other DNA Saturdays posts: https://upsdownsfamilyhistory.wordpress.com/tag/dna-saturdays/ran

 

About Wichita Genealogist

Originally from Gulfport, Mississippi. Live in Wichita, Kansas now. I suffer Bipolar I, ultra-ultra rapid cycling, mixed episodes. Blog on a variety of topics - genealogy, DNA, mental health, among others. Let's collaborateDealspotr.com
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