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  #1  
Old 28th October 2006, 03:09 PM
Cats Cats is offline
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Fathers

If you can't trace male lineage through DNA testing then how does a paternity test for fathers and daughters work? If the test shows a DNA match it means that females can be tested to detrmine male lineage. Am I correct or missing something?
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Old 28th October 2006, 11:17 PM
rivergirl rivergirl is offline
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Quote:
Originally Posted by Cats
If you can't trace male lineage through DNA testing then how does a paternity test for fathers and daughters work? If the test shows a DNA match it means that females can be tested to detrmine male lineage. Am I correct or missing something?
Not sure what you mean by "you cant trace male lineage through DNA", as you can. But the person to test needs to be male.

For genealogical purposes, the male lineage is traced back through the fathers Y Chromosome. This will only give the fathers, fathers, fathers, line, not any other line, like your grandmothers father etc..

Very simply put;
Males have an X and a Y Chromosome. (XY)
Females have two X Chromosome. (XX)

A female gets an X from her mother, and an X from her father. Being female you do not get a Y chromosome. (XX)
Your brother gets a Y from his father and a X from his mother. (XY)

You as a female, can not do a Y Chrosmome DNA test, but a brother, father or male cosin on that line can.

I dont know what DNA Paternity tests look at, maybe the X from your father, or some other autosomal DNA passed onto you???
Being a female you do not get the Y Chromsome.
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Old 28th October 2006, 11:45 PM
haplogroupc haplogroupc is offline
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Quote:
Originally Posted by Cats
If you can't trace male lineage through DNA testing then how does a paternity test for fathers and daughters work? If the test shows a DNA match it means that females can be tested to detrmine male lineage. Am I correct or missing something?
If you don't have the father's DNA sample available, there are only autosomal and X-STR tests available for the daughter and neither of them are as accurate as a paternity test. The autosomal tests will reveal both of her parents DNA without explaining which parent which marker came from. From what I understand, the X-STR would reveal her father's maternal parents (you'd have to double check that). Autosomal markers can bring up all sorts of different ancestries depending on the database they are run through. Alot of people don't take autosmal tests seriously because of it but for others they do confirm ancestry.

I've probably already mentioned this a million times on the forum but I have an ancestor from Sicily and my third highest match was Sicilia, Italy on the DNA Tribes test. I also got a match with the exact location my dad was born and also a match with the place my mom's maternal side is from. The Ancestry By DNA matched both of my parents' haplogroups. So I see autosomal as somewhat accurate.

Take a look at www.ancestrybydna.com and www.dnatribes.com

Last edited by haplogroupc; 28th October 2006 at 11:53 PM.
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Old 29th October 2006, 12:22 AM
efgen efgen is offline
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Another simplified explanation -- there are different types of chromosomes in our DNA. Genealogical DNA tests are done on different chromosomes than paternity tests. The most common tests for genealogy (Y-DNA and mtDNA) cannot test a woman's paternal line. However, a woman's brother or father (or even an uncle, nephew or male cousin from her paternal line) can take the paternal (Y-DNA) test on her behalf.

See the following for some basics on genetics:

http://www.ftdna.com/tutorial_A.html
https://www3.nationalgeographic.com/.../overview.html

Last edited by efgen; 29th October 2006 at 12:35 AM.
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  #5  
Old 29th October 2006, 12:36 AM
haplogroupc haplogroupc is offline
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Quote:
Originally Posted by Cats
If you can't trace male lineage through DNA testing then how does a paternity test for fathers and daughters work? If the test shows a DNA match it means that females can be tested to detrmine male lineage. Am I correct or missing something?
Is she the one who was adopted and therefore doesn't have any known siblings who can take the tests?
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  #6  
Old 29th October 2006, 02:12 PM
tomcat tomcat is offline
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Quote:
Originally Posted by Cats
If you can't trace male lineage through DNA testing then how does a paternity test for fathers and daughters work? If the test shows a DNA match it means that females can be tested to detrmine male lineage. Am I correct or missing something?
There are several sorts of 'markers' that can be employed to demonstrate paternity - CODIS and blood factor and x-chromosome and y-DNA for male children - but all depend upon having samples from both the acknowledged and unacknowledged parent to match to those of the child.

If a mother suspected her child got switched at the hospital she could use an mt-DNA test and others to demonstrate maternity ...
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  #7  
Old 3rd November 2006, 09:38 AM
Cats Cats is offline
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Quote:
Originally Posted by haplogroupc
Is she the one who was adopted and therefore doesn't have any known siblings who can take the tests?
It is my grandmother that was adopted. Her only daughter is still alive and I hope to save enough to get her tested.
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  #8  
Old 3rd November 2006, 09:43 AM
Cats Cats is offline
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Quote:
Originally Posted by efgen
Another simplified explanation -- there are different types of chromosomes in our DNA. Genealogical DNA tests are done on different chromosomes than paternity tests. The most common tests for genealogy (Y-DNA and mtDNA) cannot test a woman's paternal line. However, a woman's brother or father (or even an uncle, nephew or male cousin from her paternal line) can take the paternal (Y-DNA) test on her behalf.
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My mother is the only living child of my grandfather. All of the grandchildren from her brothers are female. The rest of the family is back in Lithuania, somewhere. Thus the question about tracing the male line through the females.
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  #9  
Old 6th November 2006, 12:08 PM
tomcat tomcat is offline
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Quote:
Originally Posted by Cats
My mother is the only living child of my grandfather. All of the grandchildren from her brothers are female. The rest of the family is back in Lithuania, somewhere. Thus the question about tracing the male line through the females.

Your mother got one of her x-chromosomes from her father and one from her mother. By testing any of her brothers, all of whom got their single x-chromosome from their mother - your grandmother - you would, by comparison, identify the x-chromosome that came from your grandfather - your mother's father - who got his single x-chromosome from his mother - your great-grandmother.

In a year or so when the worldwide database of population frequencies for x-chromosome markers is more built-up you may be able to draw inferences about your grandfather by comparing his x-markers to the database.

There is at least one thread on this forum about 'x-testing' - you might want to look that up and read and post to it.

Tom
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