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. Please note that only Family Tree DNA with their Family Finder test or 23andMe allow you to download your raw data file so that you can upload it to GedMatch. Ancestry does NOT allow you access to your raw data.
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.
I wish I had studied more biology, I took the dna test thinking that I would find my native American ancestors. I see now that it is not as easy as all that. I found so many great surprises otherwise, and I wish I could afford some further testing. I have narrowed my search however, I would like to know my percentages more precisely on both the Y and the X lines. I wonder at the stories of all my ancestors. One thing that does really amaze me is that people can be descended from the same ancestor more than once. I am also descended from several brother and sister lines. As I followed my lines back, I see that my mothers family and my fathers family have intersected several times in history. It is amazing to me that in the court of Henry VIII, that I descend from at least 6 people that were prominent people to Henry, including Henry and his sister. LOL Now I have a book stuck in my head. Thank you Roberta for doing these explanations, as they are well worded and not quite so hard to follow in our quests.
Thank you for the blog post and the wonderful chart. I have printed off the female one and intend to use it for my X-DNA inheritance.
Regards,
Margaret Jordan
Thank you for this! Looking forward to the pdf when it comes out!!
How did you know that you and Marja were related on the X chromosome? How can we tell who is related to us on the X chromosome? That information isn’t given in our FF Chromosome browser since it only has 22 chromosomes. What am I missing here???
We knew through GedMatch.
A very interesting article Roberta – it explained a lot of things. Can you please tell me how we can tell on the X chromosome whether we have a significant match? Is it the total shared cM? Or is it the length of the longest matching segment? What length is considered significant? In the autosomal matches we look for matching segments over 7 cM. What is the magic number on the X chromosome, to be considered a significant match genealogically?
Regards
Wendy
The guidelines for the X are the same. 7 cM represents a likely ancestor connection. 5-7 is a good maybe, especially if there is some paper documentation that backs it up. Less than 500 SNPs is considered probably identical by state without anything else. I think Tim Janzen likes to see 700 SNPs and more than 7 cM. Having said that, of course if you have a match above that threshold, then the smaller matches are more likely to be by descent instead of by state. By state means that you share a general population and by descent means you share a common ancestor in a genealogical timeframe.
Thank you for your help in understanding this. May I ask another question? When I sort my X Gedmatch results by total shared cM, my top 10 results range between 60.2 and 86.9 cM with largest segments mostly over 10 cM and up to 17.9 cM. But all the 10 XDNA matches have 0 in the autosomal side. How can this be? And what is the significance? (Incidentally, a match with one of your kits comes in at 11 cM and 57.9 shared total – also with 0 on the autosomal side.)
Regarding the autosomal ), it sounds like a bug to me. You need to contact John or Curtis at GedMatch and ask them.
Regarding what is a good match, it’s both the cM length, generally over 7, and the total number of SNPS in that segment, generally over 500.
Hi Roberta,
Thanks for this clear explanation of X DNA. I have a question I hope you may be able to help me with, my Dad and I both have a match with a woman whom I believe she is probably related through my paternal grandmother’s ancestors from a particular county in Ireland where all this woman’s known ancestors also lived. Using the X chromosome inheritance chart, my Dad could have potentially inherited X DNA from those ancestors. However, on Gedmatch my Dad shows just one matching section on the X chromosome 4.0 cM/387 SNPs with this woman, while I show eight matching sections over 3 cM including 7.8 cM/751 SNPs and 7.1 cM/545 SNPs. Does this mean I am also related to this woman through my maternal line? Thanks for insight you can offer.
Remember when you’re dealing with segments this small, unless you have a confirmed ancestor, you could very likely be dealing with segments that are identical by state, not by descent. In your case, if you didn’t receive them from your Dad, then you received them from your Mom, or a segment from your Mom and a segment from your Dad happen to be side by side and therefore “look” like a larger segment. When you’re dealing with small segments, below 7 or minimally 5 cM and below 700 or minimally 500 SNPs, you are likely dealing with segments that are identical by state and there will be more of those in any given population than there will be segments identical by descent. After all, as you mentioned, if they are from Ireland, they came from the same population and likely shared ancestors long ago.
Thanks Roberta for your help
Great article, Roberta. I’m going to pass it on to some of my X matches who keep trying to think “mtdna” and I am obviously not getting through to them with what I’m saying.
Pingback: 4 Kinds of DNA for Genetic Genealogy | DNAeXplained – Genetic Genealogy
Thank you for this informative article, and – actually – for all of your articles. Bettinger’s charts are easy to understand, but I still have what’s probably a dumb question: When the mother passes along an X chromosome to her child, is it a new combination of her own two X chromosomes, or is it a copy of either the one she got from her mother *or* the one she got from her father? Thanks!
Not a dumb question at all. It’s a new combination of the two Xs of her parents that she inherited.
If two kits compared for x at gedmatch show zero matching segments, can one assume that the match is from one of the lines that could not contribute to the x?
Hi Lynnette. Nope, you can’t assume. It’s certainly a possibility, but it’s also a possibility that they could share pieces of the X, but the DNA simply was not handed down that way. If you have other people proven from the same “X” line, then compare them with the “non-family” person as well. The more people who don’t match at all, then the more likely it is that they don’t share an X ancestor. Good question!
Pingback: Phasing the X Chromosome | DNAeXplained – Genetic Genealogy
Maybe this is obvious, but since it wasn’t shown: for the chart with the female inheritance, viewing it clockwise, does the 2nd quarter segment (colored areas, but no percentages) at top left have the same percentages in the same blocks as the 4th quarter segment (last on right side), as shown on the male inheritance chart? Mr. Bettinger’s charts on his site don’t indicate these percentages.
BTW, I found a blank of these charts at http://dept.cs.williams.edu/~bailey/genealogy/ – the Pedigree Fan chart.
Yes, they do. They are both inheriting from the female, on both the male and female’s chart. Assuming I’m understanding what you’re asking.
Okay, to try to say it more clearly (I hope), if we look at your last fan chart in the article, does the section starting with person #9 and going back have the same percentages as the section starting with person #1, going back? It would seem so, but some of these things can be confusing to me.
Thanks so much for the article and help.
Yes, that is what I thought you meant, and yes, they are the same percentages.
Okay, thanks very much.
Is the mtdna x from the mother dominate to the x inherited from the father? Or can a girl inherit genes from both parents equaly? So how do you know which Dna a girl is carring?
Neither one is dominant. A female carries an X from each parent and they are entirely independent of each other. Traits themselves can be either dominant or recessive, but they have nothing to do with the X chromosome. Chromosomes are not dominant or recessive.
Thanks for this. I was wondering what I could do with our X-DNA matches. We were surprised to see that my wife’s “Ancestral Composition” shows some possible Native American ancestry, so this may help narrow that down.
Pingback: The Autosomal Me – Testing Company Results | DNAeXplained – Genetic Genealogy
Hello. I am a male. On Gedmatch I have the following matches on the X chromosome for which I do not know what to think:
- case1: 5.6 cM and 598 SNPs (female match)
- case2: 7.2 cM and 285 SNPs (female match)
- case3: 3.3 cM/273 SNPs and 6.8 cM/364 SNPs (female match)
according to 23andme, the following rules goes for X chromosome:
Male vs Male : 200 SNPs/ 1 cM
Male vs female: 600 SNPs/ 6 cM
according to the rule that I read on this forum (7cM 700 SNPs)
my questions are:
- Can I consider any of these ladies a potential genetical match? according to both rules the answer is no!
- I am right to consider that my closest match is case 1?
- I read that the general rule of min 5 cM 500 SNPs is accepted but every one now goes for min 7 cM 700 SNPs. what is right?
- If I may ask an autosomal question, what about a match with 8.8 cM and 696 SNPs or 6.8 cM 1300 SNPs? are they matches at all?
Thank you very much for your answer.
The reason there are different “rules of thumb” for autosomal and the X chromosome is that the inheritance path is different so the amount of DNA from an X ancestor that you inherit is different than the normal autosomal inheritance here you divide every generation by 50%. http://dna-explained.com/2012/09/27/x-marks-the-spot/
Remember that these are all “rules of thumb” too, trying to help people determine what is real in a genealogical timeframe versus what is population which means from further back in time and not necessarily attributable to a specific ancestor, although that’s isn’t always the case.
Also, it really isn’t male vs female match. Some males may not qualify at all for consideration as a match to your specific X chromosome. If they come from a part of your tree where you do not inherit an X, for example. If you are a male, then that is anyone on you father’s side of the tree, for example.
Different companies set different “rules of thumb” too, the 7.7 vs 5cM and the 500 vs 700 SNPs. It’s pretty much universal that below 5, it’s not useless, but it’s less and less likely the smaller you get in terms of SNPS and in terms of length of cM that match.
So this is not an absolute – this is a sliding scale and using the X, it depends on who and where in the tree. So, these three people are all genetic matches to you. They do match you. The question is how far back in time an can you find a common ancestor? Do they match you because you come from a common population, say German, for example and you’re all carrying some DNA that has been in that population for a long time, or is it because you share a common ancestor in more recent times? These tools, plus your genealogy will help to answer that. Mapping certain chromosome segments of yours to known ancestors will go a long way to helping to answer some of these questions as well.
Great way to write a question! We can all learn from the answer. i look forward to it!
Thank you for the answer. My quest is somehow harder than the average european since i come from a french island where admixing has been a way of life for centuries now. I am the result of mainly europeans (french, english, portuguese, spanish and italian) who mixed with malagasy (african + asian) and indians. This makes us genetically very rich but does not allow us to go beyond our acestors that traveled and settled on our island. As for me I end up matching very closely some specific europeans such as german, austrian, roumanian, etc or some russians or even some ashkenazim. I have no clue how it can be possible. Most europeans I match with values above 8 cM up to 16 cM and above 700 SNPs which would seem real matches according to the rules. Most askenazim I match at values like 6.8 cM 696 SNPs, very close to the minimum but not just it. All this made me wonder if the matches below 7 cM 700 SPNs but yet very close to the limit like my ashkenazim matches, if is was meaningful! Thank you again.
Ashkenazi and other heavyily intermarried people are a bit of a different situation. In essence, by continually intermarrying, they pass the same DNA around and back and forth, with little new admixture to add to the pot. So people from endogamous societies will show more matches that are really more distant than they appear, because as a group they carry so much of the same DNA.
I’m just trying to get this straight in my head. A female can pass her X chromosome and also her Mitochondrial DNA,the only difference is that the X chromosomes determine the sex?So a female can inherent her mothers Mitochondrial DNA,and also inherent her Fathers X chromosome that he received from his mother?
Actually, the thing that determines the sex of the child is whether the father passes his X chromosome or his Y. If he passes a Y, it’s a boy, and if he passes his X, it’s a girl. The mother always passes an X chromosome to both sexes of children and she also passes mitochondrial DNA to both sexes of children as well.