14th Great Grandmother

+2 votes
Good Day,

We are having difficulties with a potential ancester issue.    We have established using auDNA that we belong to quite an ancient paternal line that can be traced back to the 15th century and is mostly in the same place, Berkshire here in the UK.  We also have established that there is some kind of link with another family line which can be traced back to the 1st century here in the UK.  The problem is that the link is by way of a 14th Great Grandmother who we believe married into the Berkshire line and then remarried into the other line.  As far as we can make out no further intermarrying between the two lines occured after (and we are unaware of any before).   The question is:  If we take a Ychrom test, although it will not be able to link directly to the 14th Great Grandmother, might it link to males from her second marriage?   At present we are under the assumption that mothers only pass X information.   In which case might X Chrom research be the best option?  The problem there is that she is the 14th Great Grandmother on my fathers side!?   Yours vexedly....
in Genealogy Help by John Davis G2G1 (1.6k points)
edited by John Davis

2 Answers

+4 votes
Best answer
When using auDNA beyond 3rd cousins you have to use triangulated groups.  Even then auDNA will not help with confirming ancestry back to a 14th great-grandparent or the 15th century.

You can use Y-DNA but that requires direct paternal line descendants.  Any females in the ancestral trail breaks the direct paternal line.

Similarly you can use mtDNA but that requires direct maternal line descendants. Any males in the ancestral trail breaks the direct maternal line.
by Peter Roberts G2G6 Pilot (552k points)
selected by John Davis

Thanks again.    There is a possibility that there is male input on the first line from the line my 14th GG Grandmother is from given the general geography and for that reason I am seriously considering a Y Chromosome. This would of course mean that those concerned didn't take the name of the father so a bit of a stab in the dark but, I feel worth a try because we know the names of the lines involved and we have quite good confirmation of the link between the two gene lines using auDNA taking into consideration all the problems involved above four generations back etc.
Dollar to GBP not currently favourable
Hello John,

If the Y-DNA37 is too expensive then you can order the Y-DNA12 ($59) or Y-DNA25 at https://www.familytreedna.com/group-join.aspx?code=E55624&Group=Sasser  You can upgrade to more markers using your DNA in storage the next time there is a sale.

However Y-DNA testing will ONLY help you with your direct paternal line which in your case is https://www.wikitree.com/index.php?title=Special:Relationship&action=calculate&person1_name=Davis-39218&person2_name=Ilsley-32 It will say nothing about the women those men had children with or the ancestry of any mothers.
Ok thanks
+3 votes
Have you tried looking into mitochrondial DNA?  This does pass only on the maternal line (though males will receive their mother's Mt DNA only very rarely will they pass it on.  The problem with XDNA is that the male passes on his XDNA which is the same as the XDNA his mother passed on to him, a daughter gets one of the two (or a mixture of the two).  This means it's difficult to figure out what a match means (at least I find it difficult).  I'd think it's more likely that a match of some sort will show up than in any other chromosome, but in GEDmatch it only shows up very rarely.  Oh, well, I"m still a relative beginner even though I did take a course in DNA biochemistry almost 50 years ago in graduate school.
by Dave Dardinger G2G6 Pilot (407k points)
Thank you Dave,

This is helpful if only to confirm my understanding.


Clarification: Males don't pass along their mtDNA. That's biologically impossible. Our mtDNA comes from our mother's mother's mother's mother (etc.).

X chromosome DNA is not related to mtDNA. Because a male gets one X chromosome from his mother and passes it along to his daughters (who also receive an X chromosome from their mother), X chromosome DNA matching offers some interesting opportunities to trace certain ancestral connections. The WikiTree DNA Ancestors page (yours is https://www.wikitree.com/treewidget/Davis-39218/89) includes a chart of the ancestors from whom a person received X-chromosome DNA. Your chart doesn't have much content yet because you've not connected very many relatives; see my father's chart to see the kind of information that will be displayed for a male whose family tree is more thoroughly connected. Unfortunately, over 15+ generations, even X chromosome DNA is pretty thoroughly diluted, so there's a very low probability of finding a match.

PS - That X-DNA chart is a wonderful tool that I think may be unique to WikiTree.

Thank you Ellen,

This is very clear and I find the wigit emmensely helpful.  I have just ordered a 37 Ychrom from FTDNA using a discount code from one of your colleagues so very excited about that.  The hope is that prior to my 14th GGGrandm'r there was some parternal input from the second line to the first.

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