brother recombination

[Cats]

I have test results for 4 tests.
1. me (tested ftdna)
2. mother (tested ftdna and 23andme)
3. brother-Jim (tested ftdna)
4. brother-Tom (tested 23andme)

On the X:
my mother matches both brothers 196 total
my mother matches me 195.9 total
Jim and Tom match 135.4
Jim and I match 68.6
Tom and I DO NOT MATCH AT ALL ON THE X!

Is this usual?

[prairielad]

I would say it is rarer, but not impossible.
Your mother has two X's so it will depend on which section of each of her X's you each received.

Based on your figures, I am going to assume you match Jim where he does not match Tom.

That would mean you and Jim would have received that portion of your mothers 1 X chromosome, while Jim and Tom received the same portion of her other X chromosome. I would almost assume that one of you may have received one of your mothers full X's (either her maternal X or paternal X which did not recombine)

[Cats]

On the X:
my mother matches both brothers 196 total
my mother matches me 195.9 total
Jim and Tom match 135.4
Jim and I match 68.6
Tom and I DO NOT MATCH AT ALL ON THE X!

Is this usual?

I made a mistake.
I match Jim 135.4
Tom and Jim match 68.6
How much X do brothers usually match?

[prairielad]

Here is my siblings values
Brother 1 Sister 1 76.5
Brother 1 Sister 2 118.2
Sister 3 Brother 2 95.5
Sister 3 Brother 3 142.26
Brother 2 Brother 3 104.43
Brother 2 Sister 1 97.58
Brother 2 Sister 2 95.5
Brother 3 Sister 1 118.86

Brothers can share anything between 0 and 196cM, but it is rarer if they share 0cM or 196cm

EDIT
Both my Sisters 2 and 3 received the same full X from our mother

[prairielad]

Noticed I missed listing Brother 1 to Brother 2 and Brother 3

Brother 1 Brother 2 57.37
Brother 1 Brother 3 125.4

[hazel_ion]

does your mom's two X's mix with each other to form one X that she passes to her children ?

[prairielad]

does your mom's two X's mix with each other to form one X that she passes to her children ?

Recombination between parents maternal and paternal chromosome to form a single one passed on to you does not always happen. This applies to mothers 2 X's and all the rest of mother and fathers autosomal chromosomes 1 thru 22.

You sometimes a full maternal or paternal chromosome from parent.

For example as I mentioned above, 2 of my sisters received my mothers maternal X only (Did not recombine with her paternal X)

I can confirm this due to comparing 14 family members results, My mother, maternal Aunt, maternal uncle, my father, 2 paternal uncles, paternal Aunt, and myself and 5 siblings. Also my fathers paternal 1st cousin, but his x does not apply to my family.

Picture represents X inheritance from each of my Grandparents to my immediate family (one of my sisters is not included in chart)

[hazel_ion]

Recombination between parents maternal and paternal chromosome to form a single one passed on to you does not always happen. This applies to mothers 2 X's and all the rest of mother and fathers autosomal chromosomes 1 thru 22.

You sometimes a full maternal or paternal chromosome from parent.

For example as I mentioned above, 2 of my sisters received my mothers maternal X only (Did not recombine with her paternal X)

I can confirm this due to comparing 14 family members results, My mother, maternal Aunt, maternal uncle, my father, 2 paternal uncles, paternal Aunt, and myself and 5 siblings. Also my fathers paternal 1st cousin, but his x does not apply to my family.

Picture represents X inheritance from each of my Grandparents to my immediate family (one of my sisters is not included in chart)

ok, so I would get my father's full X that he got from his mother.

and my mom's X that could be a mix of her (2) or one full from either her mom or dad.

got to love nature

[larzus]

I have tested myself (female), both my parents and my son. My son received my father's X chromosome 100%. It did not recombine at all and he is not an X-Match at all with his maternal grandmother. Not even a tiny segment! So any X-Match he has comes from his great grandmother on his maternal grandfather's side. It's quite handy.

[andreastill.gen]

I tested my paternal grandmother and one of her female half-1st cousins. The grandparent they share is a grandmother. I expected to see some sharing on the X but I was shocked to see they shared nothing! My grandmother is descended from the son of the common grandmother and the cousin from a daughter of the second marriage. If I've learned anything after embarking on the DNA journey it is that DNA can do some very unexpected things.

[Canyon Wolf]

Be careful - do not assume

I would almost assume that one of you may have received one of your mothers full X's (either her maternal X or paternal X which did not recombine)

Please take careful note of the word ALMOST in the above sentence!

I had a similar situation where a female did not APPEAR to match one of her male siblings on the X. In the process of trying to phase the X I discovered that the two did indeed have a tiny match indicating they each had a cross-over point on the X. The matching segment was less than 5cM so the default settings at both FTDNA and gedmatch were showing no match. When I reduced the cM to 3 at gedmatch it popped right out. Once I discovered this I was able to get my phasing to work out correctly (I had several other siblings to work with).

[icsssh]

Implications of a 178.2 cM X chromosome match w/ brother

My full brother and I have a 178.2 cM match on our X-chromosome, with 15,552 matching SNPs, and with the full match representing "Base Pairs with Full Match", according to GedMatch. I know that recombination of the X-chromosome is unpredictable, but I'm still not sure what conclusions I can draw from this match. Since my mother had two X chromosomes, does such a long match with full base pair matches mean that we both received one of her two chromosomes practically without recombination? It's the base pair with full matches phrase that kind of throws me.

[John McCoy]

I believe in the case of a male, the X chromosome is a "full match" simply because there is only one X ! That is, there's no logical sense to calling it a "half match" for this situation!

It is certainly possible for two siblings to end up with the same maternal X chromosome, without recombination. The odds are not very high, but there's no reason it can't happen.

[prairielad]

When comparing two males on X, it will always show a Full base pair match due to Raw Data by default is listed in double values due to each chromosome coming in pairs, except in the case of males who only have 1 X.

Raw Data lists males single values as AA, CC, GG, or TT, when in reality it is only A, C, G or T

I have two sisters that show as Full base pair match along entire length of X.
The only difference is the first tested SNP at position 1370495(build 36)