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ThaYamamoto
07-15-2020, 05:26 PM
On FTDNA, I have an X-match that seems outta the ordinary. I've always felt that 23andme's sequencing of my data has been poor with the X making little sense...this match of mine:

Mr XX: Centrimorgans 195.93 Matching SNPs:18,092

On the graphic, we share the entirety of the X chromosome. The weirdest part is from his name and haplogroups (ydna=I, mtdna=A) we are no way near being the same ethnicity let alone related. 23andme has my X chromosome as being South Asian with the 0.1% trace Finnish they allocate to me found on the X chromosome (which is also strange considering my momz is mostly almost-no-steppe South Asian+ Tropical African). Have 23andme screwed up or is there more to this? I can post screenshots if anyone wants to have a gander.


edit: the other X match I have also shares the same Y haplogroup as the match above, but his match is tiny [around 500snps].

ThaYamamoto
07-15-2020, 06:36 PM
Mods could you move this to the genealogy section where it has a higher chance of being answered? I really need some insight into this....

ThaYamamoto
07-15-2020, 11:33 PM
Really, none yall able to help me out on this one?

Megalophias
07-15-2020, 11:48 PM
Wouldn't you have to be actual cousins or something to match that closely? You don't match on any other chromosomes?

Revmac
07-15-2020, 11:59 PM
It’s a rare thing I think, but even a brother and sister aren’t guaranteed to have an x match.

So matching someone who isn’t a parent on the whole X chromosome seems strange to me at this point.

Sorry I couldn’t be of more help.

Revmac
07-16-2020, 12:12 AM
Do you have any close linked relationships on ftdna?

If you do you might be able to figure out which ancestors your x likely comes from and extrapolate by that whether your match has any possibility of being genealogically relevant.

Another big question to ask is if you match on any other chromosomes like @Megalophias said.

ThaYamamoto
07-16-2020, 12:38 AM
Wouldn't you have to be actual cousins or something to match that closely? You don't match on any other chromosomes?

He's a 5th-to-remote match...that's what so mad about this.



Itís a rare thing I think, but even a brother and sister arenít guaranteed to have an x match.

So matching someone who isnít a parent on the whole X chromosome seems strange to me at this point.

Sorry I couldnít be of more help.


Do you have any close linked relationships on ftdna?

If you do you might be able to figure out which ancestors your x likely comes from and extrapolate by that whether your match has any possibility of being genealogically relevant.

Another big question to ask is if you match on any other chromosomes like @Megalophias said.

Unfortunately I only have third cousins onward on FTDNA and I've tried triangulating them and there's absolutely nothing in common with him. The fact we share an entire X chromosome but are of completely different ethnic groups, it makes no sense right? I've attached the proof following. My suspicions with 23andme basically straight juking me are seeming more and more correct. I have two other X matches but they share a tiny amount (500snps), both of them seem to be European but cuz its such a distant match, isn't that big a deal. It's just this guy. Sharing the entirety with someone who is a remote cousin...something is off here right?

Revmac
07-16-2020, 12:53 AM
He's a 5th-to-remote match...that's what so mad about this.

Unfortunately I only have third cousins onward on FTDNA and I've tried triangulating them and there's absolutely nothing in common with him. The fact we share an entire X chromosome but are of completely different ethnic groups, it makes no sense right? I've attached the proof following. My suspicions with 23andme basically straight juking me are seeming more and more correct. I have two other X matches but they share a tiny amount (500snps), both of them seem to be European but cuz its such a distant match, isn't that big a deal. It's just this guy. Sharing the entirety with someone who is a remote cousin...something is off here right?

Yeah from that far out of a relationship it seems like you would both have to have had inherited 100% of your x from your mother’s—who have different mtDNA haplogroups—for several generations.

Yeah it can still be tough even when you have close relatives who have tested and can link to.

ThaYamamoto
07-16-2020, 01:04 AM
Yeah from that far out of a relationship it seems like you would both have to have had inherited 100% of your x from your mother’s—who have different mtDNA haplogroups—for several generations.

Yeah it can still be tough even when you have close relatives who have tested and can link to.

Thanks for responding man, I didn't even know it was that improbable. Wow. I mean my maternal haplogroup is L3b1a, making it even more ridiculous that we'd share the same ancestry. Crazy. If anyones interested, I tested with 23andme literally as they were implementing the v5, in fact my first raw data report read v4, when it changed and I hit them up about it, they denied it. I've had issues with this damn company since. This vindicates it. I'm sure they're good for the majority of folks, but they've juked me. Ancestry should come through in the next few days, if I X-match with this guy again wit their data, then I really don't know what's going on. Thanks @Megalophias as well, preciate it.

Kellebel
07-16-2020, 01:34 AM
Thanks for responding man, I didn't even know it was that improbable. Wow. I mean my maternal haplogroup is L3b1a, making it even more ridiculous that we'd share the same ancestry. Crazy. If anyones interested, I tested with 23andme literally as they were implementing the v5, in fact my first raw data report read v4, when it changed and I hit them up about it, they denied it. I've had issues with this damn company since. This vindicates it. I'm sure they're good for the majority of folks, but they've juked me. Ancestry should come through in the next few days, if I X-match with this guy again wit their data, then I really don't know what's going on. Thanks @Megalophias as well, preciate it.

I'm afraid Ancestry doesn't use the X Chromosome with DNA matches - nor would it matter, as we can't even see on what segment or even chromosome we match over there.

Revmac
07-16-2020, 01:34 AM
No problem, I wouldn’t take my understanding for an authority on the subject though. Hopefully someone more knowledgeable than I will respond!

The X chromosome is very complex. So, I doubt that I did it justice.

ThaYamamoto
07-16-2020, 01:38 AM
I'm afraid Ancestry doesn't use the X Chromosome with DNA matches - nor would it matter, as we can't even see on what segment or even chromosome we match over there.

I believe they genotype the '23rd' chromosome which is the X, but you can't see it like you said cuz of no chromosome browser...maybe I'm wrong though. Tha plan was to upload their data to ftdna where they'd match the X/23rd from ancestry's data. Either way whatever 23andme have done is big mad.

Revmac
07-16-2020, 01:40 AM
I'm afraid Ancestry doesn't use the X Chromosome with DNA matches - nor would it matter, as we can't even see on what segment or even chromosome we match over there.

Indeed they donít, Iíve never used 23&me but Iíve heard that their x matches are mostly useless from others. I couldnít make a judgment for myself though.

Kellebel
07-16-2020, 01:44 AM
I believe they genotype the '23rd' chromosome which is the X, but you can't see it like you said cuz of no chromosome browser...maybe I'm wrong though. Tha plan was to upload their data to ftdna where they'd match the X/23rd from ancestry's data. Either way whatever 23andme have done is big mad.

They do genotype it, but don't use it in their DNA matching tool. They also don't use certain Pile-Up regions in matching I believe. But perhaps that FTDNA plan works out, fingers crossed!

And yeah, 23andMe's matching system has become weak to say the least. Ever since the new chip, I've had a tremendous amount of IBC matches. 23 isn't what it used to be anymore - although imho they're still the best commercial testing site out there: but that says more about their competitors than them to be frank.

Kellebel
07-16-2020, 01:47 AM
Indeed they don’t, I’ve never used 23&me but I’ve heard that their x matches are mostly useless from others. I couldn’t make a judgment for myself though.

Idk about others, but mine are useless aswell. A lot of matches that don't make sense whatsoever - like having whole different ethnicities. Nothing I can work with anyway.

ThaYamamoto
07-16-2020, 01:55 AM
They do genotype it, but don't use it in their DNA matching tool. They also don't use certain Pile-Up regions in matching I believe. But perhaps that FTDNA plan works out, fingers crossed!

And yeah, 23andMe's matching system has become weak to say the least. Ever since the new chip, I've had a tremendous amount of IBC matches. 23 isn't what it used to be anymore - although imho they're still the best commercial testing site out there: but that says more about their competitors than them to be frank.

Ahh okay, I get you. Damn, guess I'll just have to see then. I haven't tested wit anyone else but for me, they the worst both in terms of matching and however they compute ancestry. My raw data is almost like a low coverage file. But most people seem to be satisfied wit em I guess.

Revmac
07-16-2020, 02:07 AM
But perhaps that FTDNA plan works out, fingers crossed!

I definitely agree with you! It seems like all of the companies that offer x testing are in their own ways lackluster.

Kellebel
07-16-2020, 02:13 AM
Ahh okay, I get you. Damn, guess I'll just have to see then. I haven't tested wit anyone else but for me, they the worst both in terms of matching and however they compute ancestry. My raw data is almost like a low coverage file. But most people seem to be satisfied wit em I guess.

Do let us know about FTDNA though, it would be interesting to see if your little loophole works!

As for 23, let me elaborate: with "the best out there", I really mean the least bad - ofcourse, it also depends on what you're expecting and what's currently possible: genetic testing is very new and has its limits. But the AC on a regional level and the matching (especially when phased) are both quite good compared to others. There's other companies, like MyHeritage, whose Ethnicity Estimate is a big joke, but their matching in combination with their familytrees is awesome. And Ancestry for example is okay-ish for the ethnicity part (if you know how to interpret it, that is), but the matching is useless with no information - the only thing I still use Ancestry for, is my familytree and ThruLines. So, all in all, that's why if I had to test all over again, I would go for 23 (first). But 23 definitely has its issues of which I've had my share aswell, don't get me wrong!

C J Wyatt III
07-16-2020, 02:16 AM
Just think of the X-chromosome as a big pile-up region and don't waste anytime on it. Spend your time on something else and you will be better off.

What drives the big (distant) X-matches, I believe, is the same factor behind pile-up's.

ThaYamamoto
07-16-2020, 02:30 AM
Do let us know about FTDNA though, it would be interesting to see if your little loophole works!

No doubt no doubt, I will do.


Just think of the X-chromosome as a big pile-up region and don't waste anytime on it. Spend your time on something else and you will be better off.

What drives the big (distant) X-matches, I believe, is the same factor behind pile-up's.

No idea what a pile up is, but I'll take your word for it.

Kellebel
07-16-2020, 02:35 AM
No doubt no doubt, I will do.



No idea what a pile up is, but I'll take your word for it.

A pile-up region is a segment which is typically shared more than usual. These are some known pile-up regions:

https://isogg.org/wiki/Identical_by_descent#/media/File:Table_3_start_and_stop_positions.jpg

Ibericus
07-16-2020, 08:47 AM
I know it's an outlandish theory but would it be possibly for an XYY individual to have his additional Y interpreted as an X? He would therefore 100%-match with other XYY men.

geebee
07-16-2020, 03:24 PM
Itís a rare thing I think, but even a brother and sister arenít guaranteed to have an x match.

So matching someone who isnít a parent on the whole X chromosome seems strange to me at this point.

Sorry I couldnít be of more help.

I don't think it's necessarily rare for close relatives to match on the whole X chromosome. The most obvious example is that sisters always will, as long as they have the same father.

However, it's also possible for siblings to match on a maternal copy of the X chromosome. My brother Bernie and my sister Kim match on their entire maternal copy -- which of course is my brother's only copy. And because my sister matches my brother's whole X, she also matches my brother's daughter Stephanie's whole X.

38539

I match most of this X. The only difference is that where these siblings' (maternal) X came entirely from our maternal grandfather, my X has about 20 cM surrounding the centromere that came from our maternal grandmother. And since I passed on to my daughter Kathryn a copy of my only X chromosome, my sister matches my daughter's X the same way I do. (It isn't exactly the same, but only because both my sister and my daughter have two X chromosomes, which can make it appear that some matching exists where it really doesn't.)

38540

Finally, because my niece Stephanie inherited a copy of my brother's X, and my daughter Kathryn inherited a copy of my X, Stephanie and Kathryn match each other the same way that I match my brother. (Again, there's a very slight apparent difference which is due the fact that two males will always have the most accurate comparison on the X.)

38542

And just for fun, here's a comparison between my niece Stephanie and my sister Kim, Kim's daughter Sarah, and Sarah's son Drake.

38543

Of course, all of these folks above are close relatives. I agree that it would be strange to share the whole X chromosome with someone who is not a close relative.

geebee
07-16-2020, 03:35 PM
I know it's an outlandish theory but would it be possibly for an XYY individual to have his additional Y interpreted as an X? He would therefore 100%-match with other XYY men.

It seems to me this would be quite obvious to any testing companies. A second Y would not be interpreted as an X chromosome, because the SNPs are not the same at most locations. The exceptions would be mainly in PAR1 and PAR2, the pseudoautomal recombining regions. But the SNPs in these regions are not counted as part of the Y chromosome, anyway.

That's why 23andMe includes these SNPs with the X chromosome, making it appear as if men have two copies of the X at the beginning and end of the chromosome. They really don't, and one copy of each of these SNPs is actually located on the Y chromosome. But since the company can't tell which are really on the X and which are really on the Y, they include them with the X.

geebee
07-16-2020, 03:45 PM
Indeed they donít, Iíve never used 23&me but Iíve heard that their x matches are mostly useless from others. I couldnít make a judgment for myself though.

You've heard wrong. I have found X matches to be extremely useful. If some others haven't, that's unfortunate for them. But I don't believe I'm alone in finding X chromosome matches very useful.

geebee
07-16-2020, 04:08 PM
Idk about others, but mine are useless aswell. A lot of matches that don't make sense whatsoever - like having whole different ethnicities. Nothing I can work with anyway.

Well, keep in mind that matching and "ethnicity analysis" are entirely different things. I'd place less reliance on the latter, but there's no reason matching on the X chromosome should be any less reliable than on any of the autosomes. In some cases, it should be more reliable, as for example in a comparison between two males.

Here's a match between one of my brothers and a third cousin twice removed:

38544

This cousin is actually related to us in multiple ways, but since I know that my brother's X chromosome came entirely from our maternal grandfather, the first thing the sharing on the X chromosome tells me is that the match is on our mother's side. But not just our mother's -- we also know it's through her father, and her father's mother. So at least these two X chromosome segments can be traced to a specific great grandmother.

But I can do better than that. By comparing my family tree -- which is of course identical to my brother's, at least "upstream" -- to this cousin's family tree, I've been able to determine the closest possible "X chromosome ancestor" for both of us.

This person is Rachael Jones Sizemore, my 4th great grandmother and my cousin's 3rd great grandmother and his 2nd great grandmother via different paths.

I could actually produce many other examples of how I've been able to make use of X chromosome matches, but I hope this is enough to show they aren't "useless".

ThaYamamoto
07-16-2020, 05:32 PM
Well, keep in mind that matching and "ethnicity analysis" are entirely different things. I'd place less reliance on the latter, but there's no reason matching on the X chromosome should be any less reliable than on any of the autosomes. In some cases, it should be more reliable, as for example in a comparison between two males.

Here's a match between one of my brothers and a third cousin twice removed:

38544

This cousin is actually related to us in multiple ways, but since I know that my brother's X chromosome came entirely from our maternal grandfather, the first thing the sharing on the X chromosome tells me is that the match is on our mother's side. But not just our mother's -- we also know it's through her father, and her father's mother. So at least these two X chromosome segments can be traced to a specific great grandmother.

But I can do better than that. By comparing my family tree -- which is of course identical to my brother's, at least "upstream" -- to this cousin's family tree, I've been able to determine the closest possible "X chromosome ancestor" for both of us.

This person is Rachael Jones Sizemore, my 4th great grandmother and my cousin's 3rd great grandmother and his 2nd great grandmother via different paths.

I could actually produce many other examples of how I've been able to make use of X chromosome matches, but I hope this is enough to show they aren't "useless".

I don't think X matches are uselesss - I'm completely new to genealogy and matching its not my forte at all. What do you reckon is going on with my match?

Revmac
07-16-2020, 11:37 PM
Well, keep in mind that matching and "ethnicity analysis" are entirely different things. I'd place less reliance on the latter, but there's no reason matching on the X chromosome should be any less reliable than on any of the autosomes. In some cases, it should be more reliable, as for example in a comparison between two males.

Here's a match between one of my brothers and a third cousin twice removed:

38544

This cousin is actually related to us in multiple ways, but since I know that my brother's X chromosome came entirely from our maternal grandfather, the first thing the sharing on the X chromosome tells me is that the match is on our mother's side. But not just our mother's -- we also know it's through her father, and her father's mother. So at least these two X chromosome segments can be traced to a specific great grandmother.

But I can do better than that. By comparing my family tree -- which is of course identical to my brother's, at least "upstream" -- to this cousin's family tree, I've been able to determine the closest possible "X chromosome ancestor" for both of us.

This person is Rachael Jones Sizemore, my 4th great grandmother and my cousin's 3rd great grandmother and his 2nd great grandmother via different paths.

I could actually produce many other examples of how I've been able to make use of X chromosome matches, but I hope this is enough to show they aren't "useless".

Thanks for the response and examples! I agree with you; I was only referring to the sentiments expressed by others in regards to 23&me. Even then, Iíve never used 23&me so I couldnít make a judgment on anything about their service. Iím glad to hear that those opinions are just that; opinions.

I have had a very similar experience to yourself with my fatherís and to a lesser extent my own x matches. I did find them useful.

My father has some recent pedigree collapse on his maternal side. So, the x matches have been useful and interesting to me. Itís nice to be able to easily pinpoint parts of a chromosome to specific ancestors. When your great grandparents were first cousins (who never tested) it can be difficult and confusing to figure out exactly who gave you which parts of a specific chromosome.

geebee
07-17-2020, 02:07 AM
Thanks for the response and examples! I agree with you; I was only referring to the sentiments expressed by others in regards to 23&me. Even then, I’ve never used 23&me so I couldn’t make a judgment on anything about their service. I’m glad to hear that those opinions are just that; opinions.

I have had a very similar experience to yourself with my father’s and to a lesser extent my own x matches. I did find them useful.

My father has some recent pedigree collapse on his maternal side. So, the x matches have been useful and interesting to me. It’s nice to be able to easily pinpoint parts of a chromosome to specific ancestors. When your great grandparents were first cousins (who never tested) it can be difficult and confusing to figure out exactly who gave you which parts of a specific chromosome.

I particularly relate to you on the issue of pedigree collapse. We all have it, eventually, but it's something that shows up pretty quickly in parts of my ancestry and among some of my cousins.

For example, while I'm descended from the second husband of my maternal grandmother's mother, I'm also related to my great grandmother's first husband -- since they were 2nd cousins. So my grandmother's older half sisters are my half great aunts through their mother, but they're also my 3rd cousins twice removed through their father.

And on this same side of the family, I've got a 3rd cousin born the same year I was who is also my 3rd cousin once removed. My cousin's father is my 2nd cousin once removed, and my cousin's mother is my 3rd cousin. These two are 2nd cousins once removed to each other, and I share segments with all three -- the parents and their son.

I have another cousin whose parents were 1st cousins to each other, and again I'm related to him on both sides. Actually, this is the cousin with whom I share the X-chromosome contributor I mentioned. We also share a few segments from among the autosomes, and these may very well have followed different paths and have different common ancestors.

The thing to keep in mind about X chromosome ancestors is how many fewer you have of these ancestors than you do of autosomal ancestors. Obviously, the recent ones often will be the same people, but when you get back to ancestors who have only passed on a single segment, or a few segments, knowing that a shared segment is on the X chromosome can drastically reduce the possible pathways.

I know that if I match someone on the X chromosome and the match is greater than 20 cM in length, the DNA has to have come from my maternal grandfather's mother. By contrast, without more information I can't tell which of my eight great grandparents a particular autosomal segment might have come from.

ThaYamamoto
07-21-2020, 03:59 PM
So except for pile-up or a massive screw up from 23andme [which im more inclined to believe], no one really got any ideas as to how this has occurred?

C J Wyatt III
07-21-2020, 05:55 PM
So except for pile-up or a massive screw up from 23andme [which im more inclined to believe], no one really got any ideas as to how this has occurred?

Have you uploaded your kit to GEDmatch? I'd like to take a look.

Tolan
07-21-2020, 06:14 PM
So except for pile-up or a massive screw up from 23andme [which im more inclined to believe], no one really got any ideas as to how this has occurred?

Why are you talking about 23andMe?
It's FTDNA must be making the mistake, right?

If all of this is correct ... then it would be an X chromosome from the depths of time without having been recombined.
Is it possible?
The X chromosome that comes from the father is not recombined.
On the other hand, only the daughters inherit the X chromosome from the father.
So one cannot have an X chromosome ancestor line without recombination. At most, it's one generation.
Two or three by chance ...

You should upload your files to gedmatch and see if there is still a match!
Ask your correspondence where their file came from.
If it's not a hacked file ...

ThaYamamoto
07-21-2020, 06:17 PM
Have you uploaded your kit to GEDmatch? I'd like to take a look.

That would be great but I deleted after their acquisition, is it possible to delete data now? If so I'll upload quickly.


Why are you talking about 23andMe?
It's FTDNA must be making the mistake, right?

If all of this is correct ... then it would be an X chromosome from the depths of time without having been recombined.
Is it possible?
The X chromosome that comes from the father is not recombined.
On the other hand, only the daughters inherit the X chromosome from the father.
So one cannot have an X chromosome ancestor line without recombination. At most, it's one generation.
Two or three by chance ...

You should upload your files to gedmatch and see if there is still a match!
Ask your correspondence where their file came from.
If it's not a hacked file ...

I feel like 23andme's handling of my DNA and consequent sequencing has been abysmal but this hasn't been entirely substantiated yet. ;)

C J Wyatt III
07-22-2020, 12:36 AM
That would be great but I deleted after their acquisition, is it possible to delete data now? If so I'll upload quickly.


The site is down right now. I think GM had an attack the other day, so that does not recommend its use. However, I find GM important to my research so I tolerate any risks. I think you can always delete your kit if you have it there just for a short term use.

If and when you decide to load your kit, you can PM me the number if you do not want to post it here.

ThaYamamoto
07-22-2020, 01:04 AM
The site is down right now. I think GM had an attack the other day, so that does not recommend its use. However, I find GM important to my research so I tolerate any risks. I think you can always delete your kit if you have it there just for a short term use.

If and when you decide to load your kit, you can PM me the number if you do not want to post it here.

Thanks a lot appreciate it, will do

ThaYamamoto
09-04-2020, 09:38 PM
The site is down right now. I think GM had an attack the other day, so that does not recommend its use. However, I find GM important to my research so I tolerate any risks. I think you can always delete your kit if you have it there just for a short term use.

If and when you decide to load your kit, you can PM me the number if you do not want to post it here.

Hey man, sorry it seems you've exceeded your PM space so I couldn't link you here ;)

Helenawe
10-07-2020, 10:46 AM
23andMe offers a trove of information about your genetics and deeper ancestry.
This top DNA testing service also provides checks for genetic health risks

I thought it would fun to have my DNA analyzed, so I sent my spit to 23andMe.
It told me I was at very high risk of developing breast

tyresshawn
10-21-2020, 08:25 PM
is 23andMe trusted company?

geebee
03-11-2021, 04:14 AM
I'm afraid Ancestry doesn't use the X Chromosome with DNA matches - nor would it matter, as we can't even see on what segment or even chromosome we match over there.

You are mistaken that it wouldn't matter. It would matter less to a woman, of course, since you get an X chromosome from each parent. However, a man gets his X chromosome from his mother. So if Ancestry were to tell us that we have a match on the X chromosome, it wouldn't matter where the match was -- he would know right away that the match was on his mother's side.

In some cases, like that of my oldest brother, it would tell which grandparent the match was through. This is because my brother's entire X chromosome is from our mother's father. So in actuality, a match on his X chromosome has to be on a particular great grandmother's side -- our maternal grandfather's mother.

So, yes, it does matter.

geebee
03-11-2021, 04:22 AM
On FTDNA, I have an X-match that seems outta the ordinary. I've always felt that 23andme's sequencing of my data has been poor with the X making little sense...this match of mine:

Mr XX: Centrimorgans 195.93 Matching SNPs:18,092

On the graphic, we share the entirety of the X chromosome. The weirdest part is from his name and haplogroups (ydna=I, mtdna=A) we are no way near being the same ethnicity let alone related. 23andme has my X chromosome as being South Asian with the 0.1% trace Finnish they allocate to me found on the X chromosome (which is also strange considering my momz is mostly almost-no-steppe South Asian+ Tropical African). Have 23andme screwed up or is there more to this? I can post screenshots if anyone wants to have a gander.


edit: the other X match I have also shares the same Y haplogroup as the match above, but his match is tiny [around 500snps].

There is zero relationship between the mtDNA haplogroup and the X chromosome. My oldest brother's X chromosome is entirely from our mother's father -- it did not recombine with the X chromosome from our mother's mother. This is actually not that uncommon an occurrence, actually.

The same thing is true for my oldest sister, which means that her maternal X chromosome matches my brother's only X chromosome for its full length. Mine is almost the same, except for 20 cM around the centromere which came from my mother's mother.

Of course, my brother and sister's mtDNA haplogroup -- like mine -- came from our maternal grandmother. But you can see that this is completely different from my brother and sister's X (or maternal X) chromosome. Again, their mtDNA haplogroup and their X chromosome are from different grandparents!

So the difference between the X and the mtDNA isn't the weird part, but that two virtually-identical X chromosomes aren't called with the same ethncities. Also, it's kind of weird to match on this much of the X chromosome but on very little of the autosomes.

geebee
03-11-2021, 04:37 AM
Itís a rare thing I think, but even a brother and sister arenít guaranteed to have an x match.

So matching someone who isnít a parent on the whole X chromosome seems strange to me at this point.

Sorry I couldnít be of more help.

It really isn't at all uncommon for siblings to match on the whole X chromosome. Sisters who share the same father will always match, for example. That's because a father only has a single X chromosome to pass on to any daughter, so no matter how many daughters he has, that is the X chromosome they will get.

With mothers it's more complicated, but there are basically three possibilities. (1) She can pass on an X chromosome that is only from her father -- with no recombination; (2) she can pass on an X chromosome that is only from her mother -- with no recombination; or (3) she can pass on a recombined X chromosome with DNA from both parents.

Possibility (3) is the most common, but (1) and (2) both occur regularly. This is also not exclusive to the X chromosome. Any chromosome will sometimes be passed on without apparent recombination. For example, my daughter has several chromosomes that include DNA only from my mother, and several that include DNA only from my father, even though most of her chromosomes include some of both. Not only is this not unusual, I'd say that most of the time at least a few chromosomes will be passed on without apparent* recombination.

*I say "apparent" because what really happens is that two identical sister chromatids recombine. Since they're alike, the resulting recombination likewise matches the original chromosome.

ThaYamamoto
03-11-2021, 08:35 PM
It really isn't at all uncommon for siblings to match on the whole X chromosome. Sisters who share the same father will always match, for example. That's because a father only has a single X chromosome to pass on to any daughter, so no matter how many daughters he has, that is the X chromosome they will get.

With mothers it's more complicated, but there are basically three possibilities. (1) She can pass on an X chromosome that is only from her father -- with no recombination; (2) she can pass on an X chromosome that is only from her mother -- with no recombination; or (3) she can pass on a recombined X chromosome with DNA from both parents.

Possibility (3) is the most common, but (1) and (2) both occur regularly. This is also not exclusive to the X chromosome. Any chromosome will sometimes be passed on without apparent recombination. For example, my daughter has several chromosomes that include DNA only from my mother, and several that include DNA only from my father, even though most of her chromosomes include some of both. Not only is this not unusual, I'd say that most of the time at least a few chromosomes will be passed on without apparent* recombination.

*I say "apparent" because what really happens is that two identical sister chromatids recombine. Since they're alike, the resulting recombination likewise matches the original chromosome.

Thanks brilliant explanation geebe - I guess I must've inherited my X from my mother's father then [we know nothing about him really]. The match over at FTDNA certainly is weird, but CJ Wyatt pointed out to me that it could be a manufactured/false kit something that apparently happens often. Maybe my mother's fathers X is entirely steppe and that's why pre-update it appeared as Finnish on 23andme? And thus all my X matches tend to be Euro. Inheritance is a strange thing.

sirdan
03-14-2021, 12:50 AM
Hello ThaYamamoto
have You done your genealogy tree extensively? Here is a chart to enter ancestors whom You possibly inherited chrX. https://genie1.com.au/wp-content/uploads/X-Chromosome-Inheritance-Pattern-Males-LCoakley.png

more read here https://genie1.com.au/x-dnas-helpful-inheritance-patterns/

Sharing almost whole X with somebody must indicate relations in the not-far past.

ThaYamamoto
03-14-2021, 07:32 PM
Hello ThaYamamoto
have You done your genealogy tree extensively? Here is a chart to enter ancestors whom You possibly inherited chrX. https://genie1.com.au/wp-content/uploads/X-Chromosome-Inheritance-Pattern-Males-LCoakley.png

more read here https://genie1.com.au/x-dnas-helpful-inheritance-patterns/

Sharing almost whole X with somebody must indicate relations in the not-far past.

Hey sirdan, I haven't actually been able to as most of my family tree are dead-ends and most of the time I have little indication of where they even came from or are purported to have come from. The X match with the gentleman on FTDNA is very strange I've gotta say. This thread reminded me about this issue so I went ahead and painstakingly checked all my 300+ 23andme relatives for an X-match. I haven't even got one X-match over there. They should really put in a X-match filter would've saved me a lot of time lol.