Ancestry DNA

[Comosus]

Andrea,

I hope someone can give you some information.    

Perhaps the usefulness of DNA testing might depend on exactly what someone is trying to learn?

The whole topic confuses me and I can't find a website that answers my questions.

For example, I would love to be able to prove that my grandmother's father was the man on her birth certificate.  But can this type of line be traced?

- man to woman to man to woman/man?
- great-grandfather (?) to grandmother to father to me/my brother?

All the websites talk about the different types of DNA but what does a person do when they aren't researching a straight female or male line?

I heard from a man who was researching a certain family line (say, Smith-Bibbins).  He found some Smith-Bibbinses in the census (in another country but born in the right place) and was able to track down the only living male descendant of that family.  He and that man both submitted DNA swabs that proved they were from the same Smith-Bibbins family.  But they're both men.

My great-grandfather was illegitimate but we don't have a clue as to who his father might have been.  Unless everyone whose ancestors lived in that area gave their DNA to a DNA bank, I don't know how we might be able to crack that particular nut.

Regards,
Josephine

Unfortunately, those sort of lines cannot be done.  The only way you could get information on those lines is by finding someone descended on an all female line (if the ancestor you are interested in is female) or an all male line (if the ancestor you are interested in is male.

It's very difficult to try and prove something using DNA testing because first you need to have another contact.  For example, if trying to prove illegitimacy, you'd need a male line descendant of the possible father of the illegitimate son.  If you had the same Y chromosome, it would prove that the illegitimate son's father was the one you thought it was.  If you have different Y chromosomes, it proves he wasn't.

mtDNA comes from mitochondria, which are passed from the mother to ALL children - both boys and girls.
Y chromosomes are passed from father to son.

It's such a cliche but you need to think about what the test will actually help solve, because they are expensive.  If the test is able to solve something, you then need to think about how you're going to go about solving it - maybe you need a contact from another part of your tree to do the test as well.  However, you can of course just do a DNA test for yourself and then see if anyone matches up.

I expect soon there will be X chromosome tests.  However these would be more difficult as women have 2.  I only have 1, which has come from my mother.  However I don't know if that X chromosome came from her father or from her mother.  The same can be said for them, so it's more of a puzzle and I don't think it's available anywhere.  So in other words, a test like that would be able to tell if you have the same X chromosome or not.  What it can't tell you is the route that that particular one took to get to you, and to get to your contact.  But you needn't worry about that as I don't think it's actually available!

Andrew

[Josephine]

Thanks so much for the explanation, Andrew!

Regards,
Josephine

[ajcarroll]

Hi

Well people I went ahead and got it done. Actually I got my brother to do it! And it has proved to be worth while. We have a very close match with some people in the US and we are trying to find out where from in our ancestry line at the moment. But I it was costly and we were lucky - I can see that many people would prob get nowhere with this.

Cheers!

Andrea

[LizzieW]

Well people I went ahead and got it done. Actually I got my brother to do it! And it has proved to be worth while.

Andrea, I think that is the only sensible way to go, as Andrew pointed out, it is not very effective to try to find ancestors via the female line, more's the pity.

Liz

[Comosus]

Well people I went ahead and got it done. Actually I got my brother to do it! And it has proved to be worth while.

Andrea, I think that is the only sensible way to go, as Andrew pointed out, it is not very effective to try to find ancestors via the female line, more's the pity.

Liz

It's perfectly effective to find ancestors by the female line, as goes for the male line - Going straight up the female line is what the mtDNA test does.  The problem comes when you want to find relations to your mother's father's mother's mother's father's mother or your father's mother's father's father's father.  All mtDNA passes down the female line.  All Y chromosomes pass down the male line.  However nothing will always pass down that line.

We have 2 copies of each chromosome (one from our father, one from our mother) which each have 2 identical bits.  When forming egg or sperm, the 2 copies of each chromsomes swap DNA and then move apart.  At this point you have 2 chromosomes - the mother's chromosome will have part of the father's and vice versa.  Because these chromosomes change every generation, they're very difficult to track.  (It's much easier to understand with an animation than words)

X and Y chromosomes however are not copies of eachother and can only cross over at the very tips, that is if they do at all.  So X and Y chromosomes stay almost identical (Also, when doing the Y test what they look for are repeated sequences and their lengths, which vary.  These will be in the section that does not cross over).  While X chromosomes stay intact, they can pass down different routes.

I have 1 X chromosome, which came from my mother.  She had 2 - One from her mother and one from her father.  I've no idea which one I have, it could be either.  Then my grandfather got his from his mother, and grandmother from both her parents.  I could have any of those 3.  Once you go back further, the number increases.

If you're female, you got 1 X from your mother, one from your father.  That one came from your paternal grandmother.  The other one could have come from either of your maternal grandparents.  Your paternal grandmother's X chromosome, which you received, could have come from either of her parents.  If add on the possibilities for your maternal grandparent's parents then there are 5 possible ones in total.

Perhaps there's a reason why X chromosome tests are not done that I don't know about, but I don't know.  I think they'd be useful even if they are more complicated to work out where the relationship lies on the tree.

Hi

Well people I went ahead and got it done. Actually I got my brother to do it! And it has proved to be worth while. We have a very close match with some people in the US and we are trying to find out where from in our ancestry line at the moment. But I it was costly and we were lucky - I can see that many people would prob get nowhere with this.

Cheers!

Andrea

Just thought I'd link you to this page: http://en.wikipedia.org/wiki/Genealogical_DNA_tests (It will also be useful for those who don't quite understand what the actual test is for, what it does, and what the results mean).

Go to the Haplotype subsection of Y Chromosome Tests and it says "If the two tests match on 37 markers, there is a 50% probability that the MRCA was fewer than 5 generations ago and a 90% probability that the MRCA was fewer than 17 generations ago".  So as you can imagine, the link could be quite far back.

Andrew

[LizzieW]

Sorry,  bit confused here.  I was thinking of having to search for father's mother's father's dna.  That's why I thought it would not be effective, but I suppose anything is possible if you pay enough.

 I have no problems with the relatives on my mother's side (both parents), or my father's father's side.  It is just father's mother's father's.

I think it might be a last resort if I don't find him any other way, but I don't know what it would prove, except that perhaps his mother wasn't Spanish or Portuguese.

Liz

[Indaloman]

Andrea,

I hope someone can give you some information.    

Perhaps the usefulness of DNA testing might depend on exactly what someone is trying to learn?

The whole topic confuses me and I can't find a website that answers my questions.

For example, I would love to be able to prove that my grandmother's father was the man on her birth certificate.  But can this type of line be traced?

- man to woman to man to woman/man?
- great-grandfather (?) to grandmother to father to me/my brother?

All the websites talk about the different types of DNA but what does a person do when they aren't researching a straight female or male line?

I heard from a man who was researching a certain family line (say, Smith-Bibbins).  He found some Smith-Bibbinses in the census (in another country but born in the right place) and was able to track down the only living male descendant of that family.  He and that man both submitted DNA swabs that proved they were from the same Smith-Bibbins family.  But they're both men.

My great-grandfather was illegitimate but we don't have a clue as to who his father might have been.  Unless everyone whose ancestors lived in that area gave their DNA to a DNA bank, I don't know how we might be able to crack that particular nut.

Regards,
Josephine

Unfortunately, those sort of lines cannot be done.  The only way you could get information on those lines is by finding someone descended on an all female line (if the ancestor you are interested in is female) or an all male line (if the ancestor you are interested in is male.

It's very difficult to try and prove something using DNA testing because first you need to have another contact.  For example, if trying to prove illegitimacy, you'd need a male line descendant of the possible father of the illegitimate son.  If you had the same Y chromosome, it would prove that the illegitimate son's father was the one you thought it was.  If you have different Y chromosomes, it proves he wasn't.

mtDNA comes from mitochondria, which are passed from the mother to ALL children - both boys and girls.
Y chromosomes are passed from father to son.

It's such a cliche but you need to think about what the test will actually help solve, because they are expensive.  If the test is able to solve something, you then need to think about how you're going to go about solving it - maybe you need a contact from another part of your tree to do the test as well.  However, you can of course just do a DNA test for yourself and then see if anyone matches up.

I expect soon there will be X chromosome tests.  However these would be more difficult as women have 2.  I only have 1, which has come from my mother.  However I don't know if that X chromosome came from her father or from her mother.  The same can be said for them, so it's more of a puzzle and I don't think it's available anywhere.  So in other words, a test like that would be able to tell if you have the same X chromosome or not.  What it can't tell you is the route that that particular one took to get to you, and to get to your contact.  But you needn't worry about that as I don't think it's actually available!

Andrew

A small point but surely DNA cannot ever prove legitimacy only the likelyhood of parentage

[Comosus]

True, but if you get a complete match then the likelihood of a recent common ancestor is very high as it would be very unlikely that someone has exactly the same number of repeats of each 37 types, through chance.  If you're doing a Y chromosome test and you get a match with someone with the same surname, you could say that it's not 100%, it's more like 99.99999999999% because through chance, someone could technically have the same number of those repeats, it would just be extremely unlikely.  This is what makes DNA testing very reliable.

Andrew

[pete edwards]

God bless U tube

http://www.youtube.com/watch?v=E8NHcQesYl8

Pete