X Marks the Spot

When using autosomal DNA, the X chromosome is a powerful tool with special inheritance properties.  Many people think that mitochondrial DNA is the same as the X chromosome.  It’s not.

Mitochondrial DNA is inherited maternally, only.  This means that mothers give their mitochondrial DNA to all of their children, but only the females pass it on.  So tracking mitochondrial DNA back up your tree, it goes to your mother, to her mother, to her mother, until you run out of direct line mothers on that branch.  The mitochondrial DNA is shown by the red shading below.  The Y chromosome is blue.

Mitochondrial DNA is not one of the 23 chromosomes you obtain from both of your parents.

The X chromosome is different.  The X chromosome is one of the 23 pairs of chromosomes.  The 23rd pair is the pair that dictates the gender of the child.  If a child has an X and a Y, it’s a male.  Remember that the father contributes the Y chromosome to male children only.  If the child has two X chromosomes, it’s a female.

The inheritance patterns for the X chromosome for males and females is therefore different.  Men inherit only one X chromosome, from their mother, while women inherit two Xs, one from their mother and one from their father.  In turn, their parents inherited their X in a specific way as well.  All ancestors don’t contribute to the X chromosome.

In my paper published in the Journal of Genetic Genealogy (Vol. 6 #1) in the fall of 2010, in a paper titled Revealing American Indian and Minority Heritage Using Y-line, Mitochondrial, Autosomal and X-Chromosomal Testing Data Combined with Pedigree Analysis, in addition to other types of analysis, I analyzed my X chromosome and what it told me about where some of my Native and African inheritance came from.

At that time, the only company returning ethnicity information about the X chromosome was deCode genetics.  My X chromosome showed that I carried Native American heritage on the X chromosome as well as on some other chromosomes.

I’m going to share the part of this paper involving the X chromosome and how it can be used genealogically and in particular, to identify candidates who could have contributed this Native and African ancestry.

Blaine Bettinger granted me permission to use 2 charts in the paper and again for this blog.  Thanks much, Blaine.  He originally published them on his blog, The Genetic Genealogist, in December 2008 and January 2009 in his blogs about how to use the X chromosome for genealogy.

The first chart shown below is the male’s X chromosome inheritance chart.  You can see that he only obtains his X chromosome from his mother who inherited it from both her mother and father, but only from some of her ancestors on either side.

The next chart is the female’s inheritance chart.  She obtains her X from both of her parents.

Blaine color coded these, pink for females and blue for males, so I was then able to quickly use them to fill in my ancestor’s names.  I know this next chart looks messy, but it’s what I did and I still refer to this regularly.  I don’t’ expect you to READ this, I expect you’ll DO something like this with your own pedigree chart.  So excuse the look into my messy closet:)

I numbered the slots so that I could work with them later.

The results were quite surprising.  The first thing that became immediately evident is that I didn’t have to worry about a few lines.  On the chart below, you can see that my mother’s German lines could be immediately eliminated, because we know they were not the source of the Native American heritage.

This leaves only three individuals on the mother’s side as candidates for Native ancestry.  Those are the numbered slots between the German lines.

The people below correspond to the numbered slots above.  See, I told you that you didn’t need to read the chicken scratch chart.

5 – Naby (probably short for Abigail), last name unknown but may be Curtis, born in Connecticut in about 1793.

7 – Capt. Samuel Mitchell, born probably about 1800, possibly in Kittery, Maine or possibly in Europe, mother unknown.  This line is probably eliminated.

8 – Captain Mitchell’s wife, Elizabeth, last name unknown

Using the pedigree chart, we narrowed the mother’s side from 21 possible slots to 5 with one more probably eliminated.  Of these, mitochondrial DNA sampling of the descendants of the two women whose last name is unknown would produce the answer to the question of maternal Native or African ancestry.

The father’s side is more complex because many of his ancestors immigrated in the colonial era.  Candidates for Native ancestry are as follows:

20 – Mary, wife of John Harrold (Herrald, later Harrell), born about 1750, died in 1826 in Wilkes County, NC.  She was rumored to have been Irish.

21 – Michael McDowell, born 1747 in Bedford Co., Va. – his mother is unknown.  His father was a second generation immigrant who lived in Halifax and Bedford Counties in Virginia.

22 – Isabel, wife of Michael McDowell, probably born about 1750, surname unknown, located in Virginia.

27 – Elizabeth, born about 1765, wife of Andrew McKee of Virginia.

28 – Agnes Craven is the last slot on the chart, but not the last in the line.  Her father was Col. Robert Craven born 1696 in Delaware and was well to do.  His mother is unknown.  Robert’s wife was Mary Harrison, born in Oyster Bay, New York to Isaiah Harrison and Elizabeth Wright.  These lines appear to reach back to Europe but are unconfirmed, probably eliminating these lines.

30 – Phoebe McMahon, wife of Joseph Workman, born 1745 York Co., Pa, daughter of Hugh McMahon, mother unknown.

31 – Gideon Faires’ mother was Deborah, born 1734, possibly in Augusta Co., Va.

32 – Sarah McSpadden’s father was Thomas McSpadden born 1721 in Ireland, eliminating this line.  Sarah’s mother was Dorothy Edmiston whose father was born in Ireland, eliminating that line.  Dorothy’s mother was named Jean and was born in 1696 but nothing further is known.

33 – Martha McCamm, born before 1743, wife of Andrew Mackie of Virginia, parents unknown.

On the father’s side, we began with 13 slots, positively eliminating one and probably eliminating a second, leaving 11.  Of these, 7 could be resolved on the maternal line by mitochondrial DNA testing.  Taken together, this side of the pedigree chart is a much better candidate for both Native and African DNA sources.  Notice all of the females who have no surnames.  These are excellent places to look for Native ancestry.  On my chicken scratch version, these are highlighted in yellow.

While the X chromosomal pedigree chart analysis is not the perfect scenario, the pedigree chart has 128 slots.  Using the X chromosome narrows the candidates to 34 slots.  Genealogy narrowed the slots to 15 and focused mitochondrial DNA testing could narrow them to 6.  Further genealogy research on those ancestors could potentially eliminate them by placing them “over the pond” or by discoveries which would facilitate DNA testing.

Marja and Me

You might recall that Marja and I are also related on our X chromosome.  In this case, since she is from Finland, the probabilities are exactly the opposite.  It’s much less likely that our connection is on my father’s or mother’s British Isles lines, and much more probable that it’s through my mother’s German lines. The early colonial settlers tended to be from the British Isles and certainly the people filling the X chromosome slots from my father’s side appear to be, with names like McDowell, McSpadden, etc.

Mother’s Anabaptist line (Brethren) is the German grouping through my mother’s father and descends from France and Switzerland,although these particiular lines don’t appear to have become Brethren until after immigrating to America.  Marja also has other matches with people from the Anabaptist project.

Those end-of-line people are:

  • Barbara Kobel – born 1713 probably Scholarie Co., NY
  • Anna Maria Deharcourt – born 1687 Muhlhofan, France, died Oley Valley, Berks Co., Pa., probable parents Jean Harcourt and wife, Susanna
  • Veronica – wife of Rudolph Hoch, born 1683 Basel, Switzerland, died 1728 Oley Valley, Berks Co., Pa.
  • Susanna Herbein – born 1698, Switzerland, father Jacob, died 1763 Oley Valley, Berks Co., Pa.
  • Jacob Lentz – born 1783 Wurttemburg, Germany, died 1870, Montgomery Co., Ohio
  • Fredericka Moselman – born 1788 Wurttemburg, Germany, died 1863 Montgomery Co., Ohio

Mother’s Dutch line is eliminated, because it’s through her father’s father.  Marja and I thought that might be a possibility, but we can see from this chart that it is not.  My father also has a Dutch line that was eliminated because it came from his paternal line.

Mother’s Lutheran Palatinate line, end-of-line ancestors show below, is though Mother’s maternal line.

  • Johann Jacob Borstler – born about 1659 Beindersheim, Bayern, Germany
  • Anna Stauber – born 1659, Schaeurnheim, Germany, father Johannes Stauber
  • Johann Peter Renner – born 1679, Mutterstadt, Bayern, Germany
  • Anna Catherina Schuster – born about 1679 probably in Mutterstadt, Germany
  • Maria Magdalena Schunck – born 1688 probably Mutterstadt, Germany, father Johann George Schunck
  • Johann Martin Weber – born about 1700 Mutterstadt, Germany
  • Rudolph Sager and wife Elizabetha – born about 1669 Ruchheim, Bayern, Germany
  • Rosina Barbara Lemmert – born 1669 Mutterstadt, Bayern, Germany
  • Anna Blancart – born 1642 Mutterstadt, possibly French
  • Johann George Hoertel and wife, Anna Catharina – born about 1642, Mutterstadt, Bayern, Germany
  • Matthaus Matthess – born 1695/1715 Rottenback, Bayern, Germany, wife unknown
  • Anna Gerlin – born 1697, Windischerlaibac, Bayern, Germany
  • Johannes Buntzman – born 1695/1720 Fulgendorf, Bayern, Germany
  • Barbara Mehlheimer – mitochondrial line J1c2 – born 1823 Goppsmannbuhl, Bayern, Germany, mother Elizabetha, unmarried

Note that the mitochondrial line is indeed one of the lines that contributes to the X chromsome inheritance path, but only one of many.

So Marja, it looks like we have to be related through one of my British Isles ancestors, listed in the first part of this article, or from one of Mother’s two German groups.  Personally, I’m betting on the German groups, but you never know.  DNA is full of surprises.

The good news is that my mother’s information is also at GedMatch, along with mine and Marja’s, so by process of elimination, we can at least figure out whether to focus on the pink or the blue side of my chart.

Today, downloading your raw results to GedMatch, combined with Blaine’s X charts above, is really the only good way of working with X chromosome matches.

I’m planning to package this article as a pdf file and send it to my X chromosome matches.  You can substitute your information for mine and do the same thing.  Hopefully, your matches will then understand the X chromsome, its unique inheritance properties, and will provide their X end-of-line ancestors for you as well.

162 thoughts on “X Marks the Spot

  1. Hello, My cousin died a few years ago and her daughter,, due to some family stories to the contrary, is seeking to prove that she is related to me. My cousin’s father was my mother’s brother. Should we use autosomal to prove or disprove a genetic connection?

  2. I just read your article and have the following comments and/or qujestions.

    I consider myself (and my sister and late brother) to be 100 % LITHUANIAN, because,

    ALL of our grandparents and great-grandparents and great-greatgrandparenst have been traced ()by me) to relatioves IN LITHUANIA.

    BUT my AncestryDNA test shows that I have (could have?) ancestral connection to FINLAND and NORTHWEST RuSSIA !

    What can I do (should I do) to determine how far back my Y-DNA line will take me and also how far back my X-DNA will take me?

    How do I “send” my AncestryDNA test results to some other institution? To have ADDITIONAL TESTING done ?

    Do you think that there might have been some DNA tests performed for some of my known relatives in LITHUANIA?

    What do you recommend that I do next?

    I HAVE a lot of Lithuanian Family Names, and some given names in my Family Tree, but there are many more MISSING !

    Please HELP !

    Thank you,


    Bill Getson

  3. Roberta, You probably have answered this question before but I cannot find the answer so here goes again. What do you consider as the “minimum” X DNA cM shared to be valid? The cutoff for GedMatch, as you know, is 7 cM. If two people share multiple X segments – but at smaller lengths, say 3 or 5cM – is that still a strong indication that this shared X DNA is identical by descent and should be considered in determining the possible relationship paths connection between the two? And could sharing multiple small segments be even more significant than sharing only one 7cM plus segment? Thanks, Deborah

    • The more total cM the better and more likely the closer the match. However, the X is inclined to do things like get passed intact for a generation or so – so it’s sometimes less reliable than other chromosomes. In any case, I would use it in conjunction with other matches and be leary otherwise. One thing you do know, of course, is that there is a distinct inheritance path, so that should help some.

      • I am still a little confused. As a female,I understand the X on the father`s side, coming from his mother and being passed on to his daughters. It`s the mother`s side that has me confused. I know that X recombines and one usually takes over and the others become barr bodies? So do we only have the X that took over? Or are those Barr Bodies part of the X?. My grandfather and his brother passed an X on from their mother to some of their descendants. We know that because we all share that one common ancestor, who could have passed on an X that we all seem to have. So is that X a combined X from different relatives? I are fortunate enough to have DNA X matches with several of my relatives on two lines. Even my daughter and granddaughter have X matches to the descendants of my grandfather`s brothers line. I don`t think I am wording this very well. I know you said before that siblings could have different X matches.

  4. Okay, I’m a lot confused. DNA is my only tool to find my wife’s unknown parents,

    23andme has given her 900+ relatives (no 1st or 2nd cousins, 3rd is closest) with one KNOWN person at 128 Cm, and another with 62) Not sure of the 128 figure, but it’s close to that.

    GEDmatch shows 1500 possible matches (at least 7 Cm), but there is nothing XDNA until well down the list. Biggest I saw was about 10 Cm.

    XDNA can come from either side, as I understand it.

    Despite the small amounts of Mitochondrial DNA, Is it just the XDNA which will help track the family? If the closest 3rd cousin shares 2% of DNA, but not no XDNA, what does this prove, if anything?

    This is a time I wish I had taken courses in DNA….

  5. A second question — I may have missed the answer: HOW can someone share X-DNA but have no matches elsewhere? This seems strange!

      • “The X chromosome is autosomal, just like the other chromosomes.”

        I found that statement confusing, because I thought the very definition of an autosomal chromosome was that it was one of the 22 numbered chromosomes, not one of the sex chromosomes (X or Y). That’s still the definition offered by many sources. Is the term “autosomal” being used differently now, or is it used differently in different situations?

        In any case, the linked article is extremely informative–thank you! Enjoying this blog so much.

      • What I meant was the it gets divided in each generation like other autosomal DNA, not like Y or mtDNA where it is passed intact in each generation.

    • the X chromosome is only going to undergo recombination when in a female ancestor so it can potentially recombine half as many times through the same number of generations as the other chromosomes. (If you follow a path of male to female to male backward in time, the chromosome only gets split half as often.)

      If you have a hole in your family tree that you can “get to” with the X chromosome, it might be helpful to have the X chromosome tested.

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  10. I got my full genetic results from 23andme within the past week, so I’m just beginning to educate myself on how to use this data for genealogy. After coming across this post I decided to look at my ancestral breakdown in the chromosome view, and now I’m very confused. My overall composition shows 2.7% Middle Eastern (not a surprise given I’m half Greek) but I was very puzzled to see that the only section containing this DNA is my X chromosome – and it’s the entire X chromosome, without a trace of other ancestries on it. Is this normal? I’m male, so it makes sense that the Middle Eastern DNA could be on my X chromosome from my Greek mother, but considering I have apparently no other Middle Eastern DNA (meaning it’s fairly far back in time), what are the chances it would pass down from that unknown ancestor to me so perfectly?? Maybe it’s just a fluke and doesn’t mean anything, but I was wondering if you or anyone else has any thoughts!

  11. I’m glad the comments here are still open, as I have been trying to use the x-match function on family finder to find how distant cousins are related.

    My mother and I have both taken autosomal tests on ftDNA. However our matches on the x chromosome are quiet different. Many of our common (2nd-5th cousin) matches appear as x-matches for my mum, but not for me. How is this possible? Surely our x-matches should be the same, as I inherit my x solely from my mother.

    Could this be a technical glitch on ftDNA or am I missing something? Thanks for any help on this one!

    • You received half your mother’s 2 X chromosomes. So, your mother should match all of your matches, but you will not match all of her matches, probably about half of them, because you only got part of her 2 Xs.

    • Thanks very much for the answer, Roberta. For genealogical purposes then, the presence of an x-match would confirm that the match was from one of lines with on the x chromosome. However the ABSENCE of an x-match does not exclude the possibility that they come from the same lines, as one might not have inherited the ‘right x’. Correct?

      Also: the common autosomal matches that my mother and I have that are x matches for her, but not for me, would indicate that I have inherited other shared chromosomes from a common ancestor than are found on the x. This would seem to strengthen the genetic connection between the two families, right?

      • Correct, the absence does not exclude the possibility.

        You will match a different person from a different ancestor, shared with your mother, one day on those other segments.

      • So, Roberta, if I find an exact ‘x” segment match shared by myself, daughter and maternal cousins – would finding other cousins who match on that very same segment go a long way in confirming a common ancestor match? Or might it still just be coincidence?

      • Sorry, left out the most important “qualifier” to that question which relates to size of the x segment match – do you think a triangulated x segment of 5 cM in length would be sufficient to prove a common ancestor? Or would that also require some other form of documentation as well?

  12. Hi Roberta, Just got my son’s DNA test results in and posted on gedmatch and I noticed that he only had one match out of all with an “x” match – and it was significant in size – 27.5 cM. I share the same segment plus a bit more (28 cM) and my daughter shares a smaller portion (about 9cM) of the same segment. Does the sheer size of the x match have any significance? Do larger shared x segments indicate that the common ancestor is closer in time for example (fewer generations) or not necessarily? And would the fact that my son inherited this particular segment – -almost intact – shed any light as to which ancestor it came from, e.g. my mother or my father’s mother? To note, none of my maternal cousins match on this segment; that said, the number of cousins tested is limited to three. Thanks, Deborah

  13. Hi,
    I am female and have tested myself, my mother and a female 3rd cousin. Under what circumstances would I have an X match to someone but my mother does not?
    I should say that both my cousin & myself have this x match but not my mom. I am identified as parent/child with my mom, so adoption isn’t the answer. Do I need to get mom retested? Thanks, June

      • I’ve read the article but I’m still confused. Even if I received 50% from my mother’s father and no contribution from my mother’s maternal line, how could I possibly be an X match to my 3rd cousin who is my mother’s second cousin? Thanks again, June

      • I can’t answer that without looking at your pedigree chart. How they descend matters. So, in general, you either match because you share a common recent ancestor, or if you can’t match on the X because you share a common recent ancestor, then you match because you share a different line, or you match because it’s an identical by chance match. If it’s identical by chance it won’t triangulate with other. In general, the X chromosome is not a good tool to use for genealogy matching. I try not to use it and user others instead when possible.

  14. Hi Roberta,
    I was reading your article and noticed that we share a common set of grandparents. My 7th great grandparents are Thomas McSpadden and Dorothy Edmiston. I would like to see how this relationship show’s up through the DNA?
    I am sure the numbers would be very small but It would be nice to confirm my genealogical research using the science of DNA.
    Thanks, Jake

    • Do you have the same matches on every autosome? For example, do you have the same matches on chromosome 5 and 6? You probably don’t. The X is really no different in this regard.

  15. I have a question. I have a “match” on ancestry.com to a woman who is my fifth cousin once removed. Our common ancestor is a Henry Reynolds, b. 1757 in Chester, PA and d. 1835 in Greene, TN. Our ancestry.com trees identified him as our common ancestor. I also have a second cousin who matches this other ancestry.com member. All three of us are at GEDmatch and we share a triangulation match there on chromosome 2. So I feel confident we have all share a true match. GEDmatch shows my second cousin shares 11.9 cMs with this other person on the X chromosome (2 segments of 5.3 and 6.6 cMs each). I don’t share any DNA on the X chromosome with this third person. The odd thing is that the line of descent from Henry Reynolds to both this other person and my second cousin have a male to male, or father to son, link at some point down their lines. So, my understanding is that any DNA shared on the X chromosome couldn’t have originated with Henry Reynolds. My second cousin and the other ancestry.com member don’t have a secondary common ancestor anywhere, so I’m thinking that the two X chromosome segments they share are really too small to be a true match. Would that be a correct assumption? I see this a lot with X matches on GEDmatch. That is, I see a number of supposed matches where the line of descent from a common ancestor indicates the X DNA could not have possibly originated with that common ancestor due to two successive males in a particular line. It doesn’t give me a great deal of confidence in the X chromosome matches I see at GEDmatch…. Sorry for the long question!

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      • Im sorry, my question is really if it is possible. I have been under the assumtion that a male could only be related on the X to through a females MGM, not ever considering the possibility of him matching X to her paternal grandmothers lines.

  17. Hi, Thanks for this X support! #28. Craven is of interest… “28 – Agnes Craven is the last slot on the chart, but not the last in the line. Her father was Col. Robert Craven born 1696 in Delaware and was well to do. His mother is unknown. Robert’s wife was Mary Harrison, born in Oyster Bay, New York to Isaiah Harrison and Elizabeth Wright. These lines appear to reach back to Europe but are unconfirmed, probably eliminating these lines.” The HARRISON family migrated to SussexCoDE, then to early AugustaCoVA, now Rockingham. Harrisonburg, VA is named after them. Book: ‘Settlers By The Long Grey Trail, HARRISON and Allied Lines’, by J. Houston Harrison, 1998, is excellent. I have a few atDNA matches who have some of these folks. I’m researching a brick wall DAVIS. Sigh. Pat Davis in OH

  18. I plan to do an autosomal DNA test from Family Tree because the “paper trail” on some of my relatives is missing and I’d really like to fill in those blanks. I’m mostly interested in my father’s maternal grandfather. Is there a “interpreting autosomal DNA test for dummies,” so I’ll know how to read and interpret the results? Many thanks!

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