Genealogy Chat

Has anybody had any experience of proving relationship through DNA tests? I understand it can be done. I have a problem confirming parentage in am ancestor although I am fairly certain I have the names etc. Is it not possible to compare DNA with, for example, my DNA and the DNA of the descendents of the siblings of my ancestor in question? Martin

Some one-name Family History Societies are co-ordinating DNA tests. As I understand it you have to have someone of the MALE line with the SAME surname and supposed same ancestors. The DNA test should be a '36 marker' one to be effective at proving a link. Be warned though - its not cheap. About £120 with a discount for the FHS joint effort. Anne

Martin You shouldnt have brought this subject up, I am a world class bore on it!! There are two sorts of DNA tests involved and you need to get the right one. The Y chromosome one, which is the usual 'Family History' one, can only be done on males who have an unbroken descent through males from a common male ancestor. The 36 point test will tell whether you have that male ancestor in common - but only up to a point! This test is widely misunderstood and is granted miraculous abilities, which it doesnt have. I will try to explain! We all have 2 parents, 4 grandparents 8 ggparents and so on. Let us say you are trying to decide if you and another man, with the same name as you, have a common gt gt grandfather. You both have a Y test and it comes back with the result that you do not have this ancestor in common. You both cry a bit and go your separate ways, thinkingyou are not related and share no genes. BUT. There is a possibility that this ggparent is still your relation, but that one of you is descended from a daughter, or other female. Females do not carry a Y chromosome so that 'signature' is lost. He is still the GT Gt Grandfather of you both, but the Y chromosome test will not prove this, indeed it will deny it. But your RECOMBINANT DNA would prove that you each share his genes in the same proportion to the genes of the other 15 Gt Gt Grandparents you have. Think of the Y chromosome as a yellow marker pen, which highlights only a single, limited route through your ancestors. Sorry to go on - I am absolutely obsessed with genetics. In short, if you are going to spend £120 on a DNA test, be aware of its limited usefulness. Hope this has helped. Marjorie

Marjorie You are not boring.....far from it. Just wish I understood it all! Even though I wouldn't consider DNA testing for family trees, I saw a fascinating TV programme on mitrochondrial (spelling??) DNA which could take people back to the tribe they descended from in remote parts of the world. It's incredible to think that our bodies carry information connecting us from one generation to the next. Perhaps you could start a 'DNA for Beginners' thread to explain how all this works! I'd love to know more! Natalie

Natalie Thankyou! I must point out that I have absolutely no scientific qualifications at all (except O level physics ha) and everything I know has been gathered from reading books on the subject. It fascinates me and always has done, how nature is secretly recording who we are and where we came from! I too read about, and saw, the programme on mitochondrial DNA, and wonder just how close we are to finding the origin of the species - well, modern man and woman anyway. It has also taught me how pointless it is to talk in terms of 'race' - there are apparently very very few people indeed on the earth who are of 'pure' race. Most modern Europeans have some black genes for instance. The Japanese have a small percentage of Eskimo genes (how did THAT happen?) and so on, we are all a glorious genetic muddle. Oh, must shut up, I'm going on again... Marjorie

Its easyer to trace via a female line than a male line. is basicly what she said

Marjorie you and me should have a chat some day we both have an intrest in the subject. But you talk nicer than me about it.

Thank you Marjorie & Peter, I now understand a bit more. How fasinating that we all carry around little bits of each other. Well you know what I mean. Even more fasinating is when you do find someone who is related and you look at pictures in that family how strong the likeness some of these are, I always think it daft when someone says of a child they don't look anything like you, with so many ggg & gggg its likey they will pick up and look like someone from way back. Thank you Irene

Marjorie, Thanks for sharing all of that - just wish I had such a 'soap box issue' to expound! Another question - do you think DNA testing is risky at all? Bearing in mind the Big Brother effect - where we already all have so much personal information 'out there', do you think the results of our innocent genealogical enquiries could at some time be abused? I'm concerned, but not yet paranoid!! Many thanks once again to Martin for raising this subject and to others for shared wisdom. Regs Jane

Thanks for replies. I think I am confused!!! Basically my Grandmother (my mothers mother) was illigitimate and only child of her mother and father. Would I ever be able to prove who I think her father was (which was a second marriage to my great grandmother after my grandmother was born) by comparing DNA with a known descendent of her father from her previous marriage? If so who would need to provide samples for such a comparison? Oh dear!! I hope this is clear!! Martin

Martin no - it wouldnt be possible. The defining marker is carried from male to male and female to female. So - your mothers mitochondrial DNA would match that of grandmother and great grandmother and the same for any sisters you had. BUT, she would not have passed on any tracers of her father to any of her children as a female doesnt pass on the Y DNA at all. If she had a brother with the same father he would inherit the Y and that would be passed dwon through his male descendants. This would in NO WAY match yor Y DNA as you would have got this from your father. e.g. I would be able to trace back and prove that I am related to my grandmother, and her sisters and any daughters born to her sisters. But my brother wouldnt he'd only be able to prove he was related to our father and grandfather and any males born of males. Hope that makes sense Zoe

Martin to put it more simply There is only a slim chance of you doing so and then only if you can find 3 or 4 living desendents. as you would need tisue from your GGG/gandfather to do a direct match test. Jane Do not fear you will not suffer a BIG BROTHER wrold as It has now been proven that clones are NOT a viable thing. Dolly the sheep proved (along with other research) that Cloning is a No go situation for humans as there are to meny Inherant misstakes in each seperat strand of DNA. this is due to damage done at or after birth. even going out in the Sun dose to much damage for skin cells to be uesed. I am shore Marjorie can put it more scientificl correct and far more acurately But thats whats been found out in a nut shell

Thinking about all this last night I have come up with a simple explanation I THINK!!!! We are all fruit salad! We have 46 pairs of chromosomes. 45 of these pairs consist of half our fathers genes and half our mothers genes. So, your dad is an apple, your mum is an orange. When they got together in the fruit bowl, they produced 45 bowls which each contained half an apple and half an orange. The 46th bowl, which is the 46th gene is the SEX chromosome, which decides whether you are male or female. So your 46th bowl contains either a whole orange or a whole apple because chromosome number 46 is NON_RECOMBINANT DAN - in other words, it hasnt combined with anything. (In fact, it does combine to a tiny exgtent, so you can put either a bit of apple or a bit of orange into the 46th bowl. Now, this is oversimplification, because your mum and dad were not the first people on earth by any means, so their bowls will contain a great mush of millions of bits of fruit, apart from 46, which will contaon either an orange or an apple and a bit of mushed up fruit salad. Right. So you get together with your dream partner and in the fullness of time, you decide to merge your fruit salad. You each put ONE bowl of fruit slad on the table, for EACH of the 45 genes, making one bowl out of each pair of two, thus mixing your own genes and those incidentally of evert ancestor you have ever had, then comes the problem - number 46, is it going to be an apple or an orange? Somebody decides and there is always a whole fruit in number 46. So, every bowl contains a bit of apple, a bit of orange and bits of everything else, but only bowl 46 has a whole fruit. So it is easy in DNA Y chromosome to match whole apples with whole apples. In RECOMBINANT DNA testing, you have to go through the other 45 bowls of fruit salad, carefully extracting every different type of fruit and laying it out. I am sure you can see that, if you are an Apple, it is easy to match you with other whole apples. Your sister is an orange of course, and would appear to have no genetic connection with you - but her 45 bowls of fruit salad are exactly the same as yours. And if your two grandfathers were an apple and a plum, you will only show up as a whole apple, or a whole plum, but there will still be lots of apple and plum in your 45 bowls of fruit salad. Thinks: Have I now gone truly barking mad???? Marjorie

Hi Marjorie I've just been reading this thread, its really interesting and no I don't think you have gone mad, in fact I think I am beginning to understand. So I am right in saying if: My mum = orange My dad = apple I = 45 bowls apple + orange and 1 bowl orange Hubby's mum = pear Hubby's dad = plum Hubby = 45 bowls pear + plum and 1 bowl plum Our Daughter = 45 bowls orange + apple + pear + plum and 1 bowl orange All of which puts the phrase about bad apples in a completely new light! Sylvia

Martin et al., There's a thread from just before xmas entitled: 'Genetic genealogy - is now the time?' which might help. Mostly it will be Y-chromosomal DNA that follows the paternal line that can be most useful in proving relationships. For close relations you can use autosomal DNA (as forensic studies) and for deep materal ancestry mitochrondrial DNA. For your question you probably need to find two unbroken male lines of descent (and a couple of spare to guard against 'non-paternity events preferably). Such results will tend to either confirm the relationship OR be inconclusive. The Chris Pomery book DNA and Family History is easy to read, inexpensive, up to date and UK-centric.

Sylvia Yes, youve got it, at least the way I understand it to be anyway. Its clever stuff this testing, but not as clever as all that - it cannot give you a name, which is what we all want after all. And the Y test and the mitochondrial test only give a single line of unbroken same sex ancestry. This is mildly interesting if you turn out to be a 90 generations direct descendant from some corpse buried in a peat bog 3000 years ago, but it doesnt tell the story of all your millions of other ancestors, to whom you are equally related. The Y chromosome test is particularly misunderstood I think - Oh, I am a direct male descendant of Attila the Hun! Yes, but also a direct descendant of two million other people as well. Attila the Hun is no more important to you genetically than anyone else of your ancestry.. Marjorie

Fascinating!!! Thank you all, but I think it is back to the drawing board!! Martin

Fascinating reading...and we've known for a while that Marjorie is barking mad so her description of parentage as a bowl of fruit salad comes as no surprise at all! Since I finished my doctorate, had kids and got ill (!), I've actually done very little reading (census returns, parish registers and the latest edition of the Teletubbies magazine do NOT count!) and I think the old grey matter is getting a little decayed. Can anyone recommend any good reading material on this subject, bearing in mind it would have to be obtainable from the local library as I live miles away from a decent bookshop? Lou

Lou I knew I was taking a risk with the fruit salad analogy - my barmy secret is out! (oh, theres an ambulance at the door with some very nice young men in white coats....must go....) Marjorie PS Go into your local library and ask for 'anything by Steve Jones' - he is not the only writer, but he is easy to read and understand.

But Marjorie, you're barmy in the nicest possible way and we love you for it! I will go and ask for Steve Jones at the library. With any luck I'll come away with some books and a nice fella to brighten these gloomy wet evenings!!! Lou