Posts tagged ‘Y-DNA’

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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