Posts tagged ‘DNA’

November 24, 2014

Consanguinity & DNA Probabilities — #Genealogy #DNA #Kinship

by C. Michael Eliasz-Solomon

Stanczyk last wrote a similarly named article, “Genealogy Consanguinity & DNA“, on 25-August-2014. But in the last week, I read two blogs that made me rethink some of the comments that we received to the blog on the probabilities of autosomal DNA (the non Y-DNA and non mt-DNA). I also read a blog once by William Dollarhide that a Family Tree should represent the DNA, the Consanguinity (how much blood shared). Although I respect the tremendous body of work and prolonged expertise of Mr. Dollarhide, my immediate reaction  was, “No, it does NOT”!

So today’s blog is a mash-up of my August 25th blog, two recent blogs I read, and William Dollarhide’s blog article on the Family Tree represents the DNA.

First off, let me state my bias up front, that I believe the Family Tree represents Legally Defined Familial Relationships as held out by the Family Tree’s owner and that copies or derivative versions or edited/annotated versions are NOT valid! There has been a long history from at least the earliest dynasties of the Pharaohs and probably even older than that the “king”, let me gender-neutral the term, the monarch decides who is family and who is erased from family histories and who inherits and who does not inherit. So we see a very early reason why family trees ARE legal based. If the wife of the monarchical family could not produce a LEGAL heir to inherit or continue the dynasty, one was often adopted or perhaps produced with a surrogate spouse. So we also have a new counter argument enter on very early in the history of families … adoptions. The adopted child may or may not possess some consanguineous blood (DNA). It was not unusual for children of siblings to be adopted if they were orphaned. Or perhaps we can view more upheaval from recent times producing ad-hoc adoptions of non-kin. We need not just accept the modern day gay-couples who adopt or couples with fertility issues who perhaps adopt an overseas child , who may or may not share any consanguinity with either parent, but are none-the-less, legal family members of a family and as such should be in the family tree. We can easily recall just the upheaval of World War II where children from Jewish families were often times ad-hoc adopted in order to save the child’s life and perhaps raised to adulthood without the knowledge of their true DNA (until later). There have been many such stories.

DNA was a late 20th century discovery, so before its discovery, there was simply no way of knowing for sure that a baby arriving from its mother’s womb, was the sire of any man in particular. Here, again we find examples of mistakenly assumed child of both parents, has the DNA of the mother, but none of the father. Yet in most cases, the family tree shows the child with the couple who raised the child and were held out to be its parents (legally).

We have also seen people use a last name to pretend or to get others to think they are from a family. I am thinking now of a man who used the Rockerfeller name when he had no consanguinity with the famous family. There have also been people who claim to have been a long-lost member of the executed Romanov family. But these people are not legally related to the more famous families by their covert or overt claims of familial ties. They are not to be represented in any LEGALLY sanctioned family tree of their creation, nor anyone else’s with those famous families. These faux family members could be EXCLUDED on the basis of DNA in all probability.

We come back to the PROBABILITY portion of this article. DNA and what are the probabilities of consanguineous relatives in the autosomal DNA (not in the direct paternal or maternal lines which can be mathematically determined with reasonable accuracy). When I wrote the blog article from August 25th, people began to immediately take issue with the data visualization that I had sourced on the autosomal boxes. For example, should siblings be 50% consanguineous? In most probabilities, yes. Now let me limit probabilities where by the mother and father are both known for certain — otherwise the mathematics goes out the window.

So siblings share 50% correct? What about identical twins? Who may or may not be 100% identical in DNA. What about fraternal twins or any of the other myriad multiples that can be conceived of? Oh, their DNA probabilities are likely much higher than siblings born from separate births, maybe approaching 100% shared DNA. So now the probabilities of consanguinity are skewed for future generations depending on which child you are in direct lineage from.

Autosomal ProbabilitiesWhat is the accepted standard for probabilities? I recently read a blog by Iowa DNA Project. She included a chart from The International Society of Genetic Genealogists. I have included that chart in this article.

The chart answers most of the questions from people on my first blog that I was not able to answer definitively. Notice one caveat to those probabilities !  These are what we can EXPECT as the probabilities for shared consanguinity.

Why are they not guaranteed? Well the first answer occurred to me because of my knowledge of genetic algorithms (and high school science). The first answer is Mutations. Sometimes when the genes copied from one parent or the other, an inexact copy results in the DNA sequence. There are also a few other things that can go wrong in the sequence.

That is perhaps a nice segue to the second blog I read recently, “Why Your DNA Might NOT Match Your Parents“. This article is actually from July 3rd of this year, but which I read last week. What happens when the mother has a rare condition called Chimerism? A short explanation is the mother has two fertilized eggs in her womb, but then one twin fuses to the other and only a single baby develops and is born. In this case, the baby does NOT share DNA with the mother who is in fact the biological mother but technically shares zero consanguinity with the baby. Now Chimerism is rare but since it has happened recently, it is likely it has happened in the past (albeit rarely) of humankind. Well that really screws up the DNA. Now if you were a direct line descendant from a Chimera baby, your DNA does not match the DNA of the rest of the  family. Let that sink in.

Now without even discussing surrogate mothers or other elaborate fertility techniques or even parthenogenesis, I believe I have completely destroyed the William Dollarhide notion of a family tree being a representation of DNA (or consanguinity). I did not even touch upon infidelity, “kings-privilege”, rape/incest/forced insemination or other known or unknown “ad-hoc adoptions” that occur in family trees with/without knowledge of the family members [since DNA and its use is recent and not widely used]. Nor did we discuss legal  dis-owning or disinheritance until this sentence. Those too would impact a family tree.

Perhaps all Family Trees really are Legally Defined Familial Relationships as held out by the family tree owner! Whether we agree or not or whether we know/believe it or not, the long process of DNA replication and historical/legal edicts have irretrievably altered all of our family trees.

The author wishes to include a post-scriptum on his own Legally Defined Familial Relationships (aka my Family Tree). As for my dear wife, Teréza & I, we felt the need to utilize extreme fertility techniques  in our personal life to produce our own biological children. We have also used legal disownments, disinheritance, name changes and an annulment to separate ourselves from others who have sought to make fraudulent claims of familial status … asserted fraudulent relationships in their own utterances:   for purposes of past, present and/or future schemes to possibly gain money from me, my wife, Teréza  or any future estate and/or cause us harm and other damages!

August 25, 2014

Genealogy Consanguinity & DNA — #Genealogy #DNA #Kinship

by C. Michael Eliasz-Solomon

Genealogy_Consanguinity
Consanguinity Chart Now … by John J. Tierney used via CC rights

 This is a beautiful data visualization tool of “relatedness” (Consanguinity) between yourself and an ancestor/descendant. Stanczyk loves good #STEM.  Mr. Tierney modified his excellent chart to add, “What percentage of DNA do you share with your family members”.

Kinship is characterized by the sharing of a common ancestor(s).  Consanguinity is derived from its Latin root:   consanguineous ∴  “of common blood”.

Today, I wanted to use this excellent chart to talk about the three types of Genealogical DNA tests:

 mtDNA

Y-DNA

autosomal DNA

mtDNA / Y-DNA

This way a genealogist can determine for him/her-self what benefit each type of DNA testing offers. mtDNA is for tracing the matrilineal line (your mother/maternal side). Y-Chromosome is for tracing your patrilineal line (aka surname tracing) or your father’s side. These two dnas are for tracing direct descent as these sex-based chromosomes are copied identically from one generation to the next, not half/half as the autosomal dna chromosome’s dna. Correctly, said the mutations in mtDNA and Y-DNA are more infrequent than the non-sex based genome (i.e. autosome) and they are not mixed like the other 22 chromosome’s dna. If you follow the blue arrows (in the diagram) up/down your family tree that is your linear descent; so you mtDNA to trace your mother’s side and use YDNA to trace your father’s side to your proverbial mitochondrial-Eve or your Y-Adam. You are testing for the blue boxes in our diagram.

So what is autosomal DNA?

Genealogy_Consanguinity_dna1

Inside Red Lines – are autosomal DNA generations.

The autosomal DNA are the dna from the other 22 non-sex chromosomes pairs. Autosomal DNA testing is a genealogical DNA test that uses either autosomal STRs or autosomal SNPs. (STR’s are Short Tandem Repeats; SNPs are single-nucleotide polymorphisms.) However, testing companies do not currently offer autosomal STRs tests that use enough STR markers for genealogy. The preferred choice for both genealogy and ethnic population matching is microarray chips that use hundreds of thousands of autosomal SNPs.

Mathematically, speaking you need at least six generations back before you get enough certainty(99% certainty) to do matching to find distant cousins by using current Genealogical DNA testing. So if you do not have your 4x-great-grandparents’ (all 64 of them) surnames then you are NOT guaranteed to be able to use current DNA tests to determine your relatedness to another genealogist (and his/her ancestors who must also have six generations in their tree too).

I am thinking we are still one or two generations (35-70 years) away from using this as a viable technique that will work with any two random genealogists — mathematically speaking. Obvious exceptions are Icelandiks or Amish or other relatively closed-genetic populations who may have greater success (or counter-intuitively lesser) with fewer generations. Its all in the DNA and in the quality of the testing to catch the diversity in your genome.

You will notice that the fine chart we have been using, including the one with the red-lines (my lines) that indicate autosomal DNA testing candidates, does NOT show enough generations. It would need to be extended one more generation. So we need the surnames of 64 people with whom we only share 1.5675% of our DNA with. That is with direct descent. If we are matching to the autosome DNA  (i.e. our Nth cousin, M-times removed) then we are matching to someone who we may only share 0.0243% blood with. That is 2/100th of 1 percent !

Related Blog Article

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p style=”text-align:justify;”>Violinist’s Thumb24-January-2014 – This has many great links to other articles and includes some pertinent facts on DNA to think about. A Guaranteed thought provoker of a blog.

August 24, 2013

From The Mailbag … — #Genealogy, #Royalty, #Polish, #Szlachta

by C. Michael Eliasz-Solomon

From the Post Office Department

From the Post Office Department

The minions in the Email-Room dropped off a missive at my virtual cubicle today. Today’s question is about Polish Royalty & DNA as it relates to genealogy …

Hi, I stumbled across your blog and thought you might could help me. We are searching for my father’s ancestry and think he is a Poniatowski. My grandfather Andrzej changed his name when he came to America in 1909. The story we always heard was that he was royal. So I have my father’s yDNA markers but cannot find a surname project online for the Poniatowskis or other Polish nobles. Do you know of any? Maybe you can give me some advice? I sure would appreciate it! Thanks in advance for sharing anything.
Sincerely,
Kristian Krawford
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Kristian,

Welcome to the blog. DNA plays a role in genealogy in some ways, but it is NOT for every genealogist. It is due the certainty factor (I favor >97% certainty) takes you back beyond the number of generations that most people tracing Slavic/Polish genealogy can do UNLESS they have royal blood. Your question gives me yet another reason to endorse limited use of DNA in genealogy. I am in favor of using DNA in your case because, you want to determine if you have royal blood or not and specifically whether or not you are related to Poniatowski szlactha (nobility).

Now to the crux of your question. You have your family DNA and want to compare it. Ancestry.com has some capacity, but perhaps because they have so little Polish emphasis in their data, their DNA may be lacking from Polish genealogists families. So…

You can Google:  

  Y-DNA project of Polish Nobility families 

That led me to:

http://www.familytreedna.com/public/polish/default.aspx?section=ysnp

This web page had a very extensive list of family names with their DNA markers. I hope you can find your markers in these that are available. Notice that is “Y-DNA”. The mt-DNA will not work for you as that is the maternal/mitochondrial DNA that is passed from Mother to all children (relatively unchanged, except by mutation) and the Y-DNA is the paternal DNA passed from father to sons (23rd chromosome). The rest of the DNA is called autosomal / atDNA (see  Genealogical DNA test). This link is a good link for introduction of DNA terms to the genealogist.

Good Luck!

Stanczyk

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