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  #1  
Old 15th February 2013, 08:01 AM
SCnMD SCnMD is offline
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Testing to find mother's family - question

My mother was an only child (as was her mother). I have no info on the parentage of my maternal grandmother. I have taken every test available for females and the autosomal test, still can not definatively find a maternal relative. My question is : Would it be of any value to have one or both of my brothers tested ( Y - test )? I am trying to figure out how to determine which matches come from maternal and which come from paternal.
Thanks
Sue
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  #2  
Old 15th February 2013, 08:29 AM
tomcat tomcat is offline
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By testing a brother you would get the Y of your father that, depending how extensively you test that Y, would only provide information on your father's deep paternal line ancestry and that information would only be of use if your father's ancestry was of a single ethnicity - both his parents and his four grandparents were of a single, 'old country' ancestry. If you know that to be the case going-in, and your father's ancestry was definitely different from that of your mother, you already have the key to sorting your Family Finder matches.

If you test both brothers via 23&Me ($90 plus $89 to transfer to FTDNA) you will triple the potential autosomal information you have on your mother and you will have each of your brothers' single X chromosomes that they got from your mother - on 23&Me (FTDNA does not yet cover X) all their matches on X will relate to your mother's ancestry.

Your brothers' X's will, most likely, be somewhat different from one another as they represent a recombination of the two X's of your mother - the one X she got from her mother and the one she got from her father.

The odds do not favor the endeavor to completely phase (separate-out) your mother's autosomal data from that of your father based on three siblings' data.

Last edited by tomcat; 15th February 2013 at 08:37 AM.
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  #3  
Old 15th February 2013, 08:59 AM
Lklundin Lklundin is offline
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Quote:
Originally Posted by tomcat View Post
If you test both brothers (...) you will triple the potential autosomal information you have on your mother
Child 1 has 50% of the mothers atDNA, so testing further siblings could never triple the knowledge.

Child 2 also has 50% of the mothers atDNA, but there is an even probability that recombination causes the maternal atDNA in child 1 and 2 to overlap. So by testing child 1 and child 2 the unknown maternal atDNA is reduced from 50% to typically 25%. Child 3 also has 50% of the mothers atDNA. But on average, 50% of that maternal atDNA overlaps with child 1 and 50% overlaps with child 2. So child 3 will typically have 75% of its maternal atDNA present in child 1 or 2, causing a test of child 3 to only reduce the unknown amount of maternal atDNA from typically 25% to typically 12.5%. The actual, observed coverage will tend to deviate more and more from the expected coverage, as more siblings are tested.

Quote:
Originally Posted by tomcat View Post
(FTDNA does not yet cover X)
While FTDNA does not (yet?) match on the X, they make the raw data available to you and you can match on that on f.ex. gedmatch.


Quote:
Originally Posted by tomcat View Post
Your brothers' X's will, most likely, be somewhat different from one another as they represent a recombination of the two X's of your mother
The good thing is that all of that of the sisters X-chromosomes that matches the brothers is maternal, so if a brother matches (and discounting the unlikely event that he inherits exactly the opposite half of the X that the sister got), then the sister will be able to detect matches as maternal on all of the X that matches the brother.

Last edited by Lklundin; 15th February 2013 at 09:02 AM.
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  #4  
Old 15th February 2013, 09:00 AM
SCnMD SCnMD is offline
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Thumbs up

Quote:
Originally Posted by tomcat View Post
By testing a brother you would get the Y of your father that, depending how extensively you test that Y, would only provide information on your father's deep paternal line ancestry and that information would only be of use if your father's ancestry was of a single ethnicity - both his parents and his four grandparents were of a single, 'old country' ancestry. If you know that to be the case going-in, and your father's ancestry was definitely different from that of your mother, you already have the key to sorting your Family Finder matches.

If you test both brothers via 23&Me ($90 plus $89 to transfer to FTDNA) you will triple the potential autosomal information you have on your mother and you will have each of your brothers' single X chromosomes that they got from your mother - on 23&Me (FTDNA does not yet cover X) all their matches on X will relate to your mother's ancestry.

Your brothers' X's will, most likely, be somewhat different from one another as they represent a recombination of the two X's of your mother - the one X she got from her mother and the one she got from her father.

The odds do not favor the endeavor to completely phase (separate-out) your mother's autosomal data from that of your father based on three siblings' data.
Thanks, Yes, my parents ancestry are from completely different areas of the world. On Gedmatch I also used the " are your parents related" tool. Every result was zero. By the way - i have also tested on Ancestry. That has not helped either, ( although i have a gazillion matches there). Some i suspect may be my maternal grandmothers line, however, my maternal grandfathers ancestry comes from the same areas as hers. I will look in to the 23 & me x- chromosome test for both my brothers. Yes i realize that at this point in testing, there is no way to completely phase out mom's from dad's - just trying to narrow down my matches. Thanks for the help -
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  #5  
Old 15th February 2013, 09:19 AM
tomcat tomcat is offline
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Originally Posted by SCnMD View Post
... I will look in to the 23 & me x- chromosome test for both my brothers. ...
You can get a Demo Account at 23&Me to test drive before you buy. In addition to the 22 autosomes and X coverage, 23&Me will also yield a pretty good Y subclade for your brothers (that unfortunately is not transferrable).
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  #6  
Old 15th February 2013, 04:11 PM
SCnMD SCnMD is offline
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Quote:
Originally Posted by Lklundin View Post
Child 1 has 50% of the mothers atDNA, so testing further siblings could never triple the knowledge.

Child 2 also has 50% of the mothers atDNA, but there is an even probability that recombination causes the maternal atDNA in child 1 and 2 to overlap. So by testing child 1 and child 2 the unknown maternal atDNA is reduced from 50% to typically 25%. Child 3 also has 50% of the mothers atDNA. But on average, 50% of that maternal atDNA overlaps with child 1 and 50% overlaps with child 2. So child 3 will typically have 75% of its maternal atDNA present in child 1 or 2, causing a test of child 3 to only reduce the unknown amount of maternal atDNA from typically 25% to typically 12.5%. The actual, observed coverage will tend to deviate more and more from the expected coverage, as more siblings are tested.


While FTDNA does not (yet?) match on the X, they make the raw data available to you and you can match on that on f.ex. gedmatch.




The good thing is that all of that of the sisters X-chromosomes that matches the brothers is maternal, so if a brother matches (and discounting the unlikely event that he inherits exactly the opposite half of the X that the sister got), then the sister will be able to detect matches as maternal on all of the X that matches the brother.
That is why i thought that i would test both my brothers. BTW - You are one of my matches on FF ( on my paternal side).
Sue
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  #7  
Old 15th February 2013, 05:24 PM
SCnMD SCnMD is offline
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Quote:
Originally Posted by tomcat View Post
You can get a Demo Account at 23&Me to test drive before you buy. In addition to the 22 autosomes and X coverage, 23&Me will also yield a pretty good Y subclade for your brothers (that unfortunately is not transferrable).
Thanks for the hint !
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  #8  
Old 16th February 2013, 12:56 AM
mixedkid mixedkid is offline
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Smile The X Factor

If you have not done so yet, I definitely would recommend you test with 23 and Me. You will get far more matches -- and even though most of those matches might not answer an e-mail, matches often provide important information in their family trees or even in their ancestral name listings. What I have been doing lately too is this: I've been looking at my own X (from my mother -- I am a male so know my X comes from my mom). I'm seeing almost exclusivly Scandinavian-related segments there + Finnish, I believe. That points towards my great-grandmother, who immigrated from Sweden at the age of 14. Of course looking at ones X doesn't mean that all the genes there came directly from a maternal line (especially for women, who get a second X from their fathers) -- but it adds a layer of information that might not have been noticed before in ones family history search.

The most important advice I can give you though: Be patient. Sooner or later, perhaps within a few years time, you might receive hints as to which side of the family your various matches belong to -- good luck.

P.S. Another way to look at the X: If your brothers tested and their raw results were loaded up at GEDmatch. A matrix would be generated and you could see which cousins they pick up are related to them through their X chromosome. Then see which of those same cousins are related to you through your own X chromsomes (if I have figured this out correctly -- and I am open for review on this from other readers -- you should have far more cousins related to you through your two own X's than your brothers have).

Last edited by mixedkid; 16th February 2013 at 01:09 AM.
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  #9  
Old 16th February 2013, 08:36 AM
1_mke 1_mke is offline
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My sharing request success rate on 23andMe has gone up significantly in the past couple of months. I think the new lower cost has encouraged a lot more people who are interested in Genealogy to test.
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  #10  
Old 16th February 2013, 04:24 PM
SCnMD SCnMD is offline
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x testing

Quote:
Originally Posted by mixedkid View Post
If you have not done so yet, I definitely would recommend you test with 23 and Me. You will get far more matches -- and even though most of those matches might not answer an e-mail, matches often provide important information in their family trees or even in their ancestral name listings. What I have been doing lately too is this: I've been looking at my own X (from my mother -- I am a male so know my X comes from my mom). I'm seeing almost exclusivly Scandinavian-related segments there + Finnish, I believe. That points towards my great-grandmother, who immigrated from Sweden at the age of 14. Of course looking at ones X doesn't mean that all the genes there came directly from a maternal line (especially for women, who get a second X from their fathers) -- but it adds a layer of information that might not have been noticed before in ones family history search.

The most important advice I can give you though: Be patient. Sooner or later, perhaps within a few years time, you might receive hints as to which side of the family your various matches belong to -- good luck.

P.S. Another way to look at the X: If your brothers tested and their raw results were loaded up at GEDmatch. A matrix would be generated and you could see which cousins they pick up are related to them through their X chromosome. Then see which of those same cousins are related to you through your own X chromsomes (if I have figured this out correctly -- and I am open for review on this from other readers -- you should have far more cousins related to you through your two own X's than your brothers have).
I had thought of 23 & me a few years ago, but the reviews i read suggested that if one were looking for DNA testing for health reasons, then 23 & me was the best site. If one is testing for the sake of genealogy questions, then FTDNA is the best. I decieded then to test here and since I was a long time Ancestry.com member, tested there also. As far as your Gedmatch suggestion, I'm am sure that there are some tools that would help; especially if I also uploaded my brothers results. Thanks
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