RootsChat.Com
General => Ancestral Family Tree DNA Testing => Topic started by: Rena on Friday 15 February 13 12:31 GMT (UK)
-
Did anyone see the trailer for this forthcoming programme? I shall definitely be watching.
BBC One on 20 February at 9.00pm to 10.00pm
Eddie Izzard, the comedian, is using his own DNA as the road map to follow the migration trail of his ancestors starting his journey in the seat of humanity in Namibia then northward through Turkey and Europe. Eddie is the first person in Britain to use his own DNA to retrace his ancestors' journey across thousands of miles and nearly 200,000 years of history. A two-part special screening on consecutive days, this is the epic story of humanity’s journey from our shared origins in Africa 10,000 generations ago
-
I read a bit about it in my TV mag.
Its in two parts and the first covers his mothers ancestry - which is poignant for him as she died young. he gets to go all over the place although I'll be interested to see how they work out the migrational route they reckon his ancestors took
-
I'll be interested to see how they work out the migrational route they reckon his ancestors took
It will be based on ongoing DNA studies of the world's population such as Dr Spencer Well's National Geographic Survey:-
https://genographic.nationalgeographic.com/about/ (https://genographic.nationalgeographic.com/about/)
http://en.wikipedia.org/wiki/Spencer_Wells (http://en.wikipedia.org/wiki/Spencer_Wells)
-
Have just set my digibox to record this - sounds fascinating.
-
An interesting slant on the BBC series by Doctor Alice Roberts , which also traced the human evolution by DNA,but around the world.
Eddie's has followed this European branch in more depth.Really fascinating
Spring
-
Just watched the first programme. From what I know of the biology, the science is reasonably accurate; I enjoyed the connections that the programme developed with the various steps along the way.
This website provides some background: http://www.bradshawfoundation.com/journey/
-
Better explanation of DNA concepts 1than the Richard III programme! Having to record tomorrows edition as off to WDYTYA Live
-
I was somewhat disappointed in this programme. I thought the Alice Roberts' series "The Incredible Human Journey" covered the subject in a much more scientific way. I thought it was very misleading to state that Eddie Izzard is "Viking" on the strength of a T2f1a1 haplogroup assignment. It was also somewhat confusing the way that the haplogroups were described as "markers". It should be noted that anyone who wishes to have a detailed mtDNA haplogroup assignment needs to take a full mitochondrial sequence test. This test is not offered by BritainsDNA, the company who did the testing for the Eddie Izzard programme:
http://www.isogg.org/wiki/BritainsDNA
Family Tree DNA (the sponsors of the DNA workshop at WDYTYA Live) are currently the only company that offer the full mitochondrial sequence test.
-
Well have to say I was disappointed. The two programmes were just a series of missed opportunities. It would be interesting to see the viewing figures to see how many watched on each night and if there was a big drop off.
In my opinion the programme would have been immensely improved if they had shown the Y DNA tree and the mtDNA tree and the global map of migrations. As it was a lot of people must have been sitting there perplexed at how it all fitted together.
I would also have liked to know what it is on the DNA sequence that indicates Neanderthal ancestors. Is it just on one part of the DNA or spread all over it, what do you look for.
In short a disappointing missed opportunity in my opinion.
-
There's just a couple of things I don't understand.
How do they know that we're all descended from a single woman? And in any case, wouldn't that single woman have needed another individual to impregnate her? And where did he come from?
Also, if we are descended from a single woman, whose myriad generations of offspring went off via various routes to populate the planet, then where do all the other strands of our DNA come from?
-
And in any case, wouldn't that single woman have needed another individual to impregnate her?
At the time our common female ancestor lived there were indeed many more people living. These other people's genes do still exist, but not on our direct maternal sides. The mtDNA tests talked about only deal with our ancestors on our mother's side, i.e., our mother, her mother, her mother, her mother, etc. Read:- http://en.wikipedia.org/wiki/Mitochondrial_Eve (http://en.wikipedia.org/wiki/Mitochondrial_Eve)
Similarly, Y-DNA tests only deal with the our ancestors on our direct paternal side, i.e., our father, his father, his father, his father, etc and can only be taken by males as Y-DNA is only passed from father to son, and not from father to daughter or mother to son.
The DNA of all of the other people that were alive millions of years ago (including Neanderthals, etc) DOES live on in the form of autosomnal DNA which is found in all of our "middle" lines, i.e. our father's mother, our mother's father, etc.
The 3 different types of DNA test (atDNA, mtDNA & Y-DNA) are explained here:-
http://en.wikipedia.org/wiki/Genealogical_DNA_test (http://en.wikipedia.org/wiki/Genealogical_DNA_test)
-
How do they know that we're all descended from a single woman?
As a biology teacher, perhaps I can be allowed to explain a bit; some of the DNA experts on here may well object to some of my simplifications and analogies, but I hope this will be useful.
This response applies only to the female line.
In every cell there are structures called mitochondria. It's believed that deep, deep in the evolutionary past the mitochondria were independent cells which in some way took up residence inside other cells. The consequence is that the mitochondria have their own DNA; and that new mitochondria are only ever formed by division of pre-existing mitochondria, in a sort of parallel way to the method of bacterial reproduction.
Now at fertilisation, only the egg cell contributes mitochondria; the sperm cell does not. So each individual human's mitochondria are clones of the mitochondria in the egg, and therefore of the mother.
Every time a new mitochondrion is formed, the mitochondrial DNA has to be copied for the new mitochondrion. This is done by some really exquisite biochemistry and with quite amazing accuracy, but there is an error rate, although it's very small. Some of these errors have no effect on the body; a few are catastrophically lethal; some have lesser adverse impact. The copying process is not intelligent so mistakes are random.
DNA is a wonderfully constructed molecule. For the purposes of this discussion, think of it simply as a long line of subunits, which are labelled A, C, G and T; the sequence of these subunits ACTTGACCTA or whatever is the genome, the set of instructions for constructing and running our cells. It is now possible to sequence lengths of DNA accurately and reliably, with high levels of automation.
Back to the mitochondria and the copying process. My analogy here is the scriptorium of a monastery. Imagine manuscript A. It's copied out by two monks Brian and Charles, but they have the extra difficulty that it's in a language they don't know. However careful they are, it's likely that they'll make mistakes. This gives us manuscripts B and C, with different errors.
Manuscript B then gets copied by two monks, David and Ethelred - copy D will have the errors of Brian and David, copy E those of Brian and Ethelred. And so on....
So an expert studying the 20th or 30th generation copies of manuscripts would be able to judge (a) whether the manuscript in question originated with Brian or Charles, by looking for their specific mistakes; and by comparing the numbers of different errors (b) how recent the shared original was - for example, C and D will be more similar to each other than to E. To use an analogy within an analogy, the scholar could create a family tree of the various copies.
This would be easier for our scholar if all the monks were equally incompetent - for example, if they each made on average a one-letter mistake per page. This is unlikely with monks, but seems to be approximately true for the mutations in the DNA. So we can treat this as a sort of molecular clock.
Very roughly, the DNA researchers have been able to look for differences in DNA sequence and therefore establish all sorts of interesting things. What differences are there? How similar are mitochondrial DNA sequences from different places? And therefore when did different mutations happen, leading to the sort of deductions made in the Eddie Izzard programmes or on the website (see my earlier post).
The other fortunate piece of biology here is that the Y-chromosome with its DNA sequence is inherited in the male line only: men have one Y-chromosome which is passed on intact in Y sperm which if fertilised will lead to male children. So you can apply the logic above to this line, as was done in the second Eddie Izzard programme.
The behaviour of the rest of our DNA - the vast majority of it, in the other 22 pairs of non-sex chromosomes (autosomes) and in the X-chromosome, is very much more complicated, and forms the basis of the autosomal DNA tests that are also available. Suffice it to say that the DNA is shuffled and reshuffled every time that eggs and sperms are formed, and that therefore neat lines of descent don't work in the same way.
I hope this helps......
-
I think I'm beginning to understand now. I'm going to read it again later when I've got a little more time to take it in. Genetics was always a weak subject for me and that was before anyone even thought about DNA.
And as someone who comes from the 'home' of DNA analysis, that's shameful. ::)
-
Thank you Graham for your explanation, it has helped me understand a little more.
-
Delighted to help. Today is almost exactly the 60th anniversary of the discovery of the structure of DNA. Amazing the changes that have happened in that time. Molecular biology has become a powerful new science: and it's impressive that this was foreshadowed in the original Watson and Crick paper in Nature.
-
I love learning about DNA and the Ancestors. What I had learnt about the One Woman
for all humans was that there was about 20,000 people in the whole World at one time
just after the Yellowstone Park blew up. The World was covered by ash and darkness and lots of things died off.
What I presume happened was that A Woman then gave birth to say 10 daughters. She then would have the multiplication you needed to spread humans around the planet as it did happen
through many thousands of years. We have learnt from looking for our Ancestors that even 15 children was normal in the Victorian times. I presume it doesnt mean she had them all from the same male donor. That would give them a good chance of surviving due to the different DNA
that each of these children had although they had the same mitrochondria. So sisters would continue the female line and still be able to breed with different males. I would imagine it was similar to the family life of many matriacal animals who treasure their breeding females like Wolves and Meercats and have lots of males to look after them and protect them. Thats my interpretation
regards Sandymc
-
I would also have liked to know what it is on the DNA sequence that indicates Neanderthal ancestors. Is it just on one part of the DNA or spread all over it, what do you look for.
The second programme was rather confusing. It purported to document Eddie Izzard's paternal line. However, there is no Neanderthal DNA on the human Y-chromosome or in human mitochondrial DNA. There are traces of Neanderthal DNA in all non-Africans but the Neanderthal is found in autosomal DNA. I don't know why they made such a fuss of Eddie Izzard's Neanderthal percentage as it was nothing out of the ordinary. The 23andMe test and the new Geno 2.0 test both give you your Neanderthal percentages. I am supposedly 2.5% Neanderthal. I've tried to include a screenshot but I'm not sure if it will come out.
The Geno 2.0 test also gives you your Denisovan percentage, but this seems to be rather experimental and I'm not sure that the results are accurate.
-
I should also add the the Izzard programme will soon be completely out of date. There is a new paper coming out this week in the American Journal of Human Genetics from Michael Hammer's lab at the University of Arizona which now puts the date of Y-chromosomal Adam at over 300,000 years before present. In the Izzard programme they gave the date as 142,000 years before present. Michael Hammer was one of the speakers in the DNA workshop at this year's Who Do You Think You Are? Live.
-
@ DevonCruwys
Thanks for that explanation on the neanderthals, most hopeful. Yes I thought the programme was not a patch on what it could have been.
I saw the Geno 2.0 test mentioned the other day (ftDNA) but I'm not at that stage yet, still trying to get a meaningful match for my yDNA test
-
There's just a couple of things I don't understand.
How do they know that we're all descended from a single woman? And in any case, wouldn't that single woman have needed another individual to impregnate her? And where did he come from?
Also, if we are descended from a single woman, whose myriad generations of offspring went off via various routes to populate the planet, then where do all the other strands of our DNA come from?
I'm glad you asked these questions. I had similar very simplistic questions whilst watching the programme. I find it all really difficult to get my head around. ;)
[Graham, your excellent explanation really helped, and as far as I am concerned, the simpler the better.]
A couple of stupid questions: If all our dna leads back to Africa, and Eddie's was shown to have originated in two different parts of Africa, so where did those different groups of humans come from? Might the dna trail lead somewhere else prior to Africa? Where did Neanderthals originate? Might there have been other groups of humans that we may not know about? The programme mentioned the Australian aborigines migration from Africa, but what about the people in the Americas - are they also from Africa?
When the scientist guy (sorry can't recall his name) said that humans share 40% of their dna with bananas, though interesting, that seemed to make other dna statistics he spoke of less relevant in a way .... :-\
-
This is one theory. http://www.youtube.com/watch?v=JnAROk72seg&feature=share&list=PL6c263DjuawSZWRCvP784u0_muQ_l5RYP
-
This is one theory. http://www.youtube.com/watch?v=JnAROk72seg&feature=share&list=PL6c263DjuawSZWRCvP784u0_muQ_l5RYP
Thanks. :)
-
As for the Americas, there is plenty of controversy because there is (as yet) not enough hard DNA and archaeological evidence. The agreed answer is that the Americas were populated via a land bridge across the Bering Strait; it seems, just as in the Izzard programme and the migration from Africa, that the founding population of the Americas was very small, with some interesting consequences on gene frequencies (for my biologist colleagues, allele frequencies!). The YouTube clip linked above is a version of the website I linked in a previous post: I prefer the website as it's a bit more interactive.
-
This is all very technical; for Mr and Mrs Average who watch TV, I think the programmes were set at just about the right level, and obviously a lot about DNA was left out.
Interesting programmes, but not for the geneticists among the members of RC !!
-
There is an excellent article in the Guardian by Mark Thomas, Professor of Evolutionary Genetics at University College London, which provides further context on the Eddie Izzard programme:
http://www.guardian.co.uk/science/blog/2013/feb/25/viking-ancestors-astrology
This blog post by Razib Khan might also be of interest:
http://blogs.discovermagazine.com/gnxp/?p=20224#.USy5izBUF5c
DNA testing is a very useful tool for genealogical research but it cannot tell you that you are a Viking, Norman, Anglo-Saxon or Celt.
-
DNA testing is a very useful tool for genealogical research but it cannot tell you that you are a Viking, Norman, Anglo-Saxon or Celt.
Oh that's no good! :( My OH keeps saying he is a Viking. I keep telling him he isn't. I was going to buy him a test to prove that I was right. ;D Will I be wasting my money? :(
(Just looking at the link you provided above which I think may answer my question ;))
-
DNA testing works well for genealogical research. For that your OH would need a standard 37-marker Y-DNA test. That would allow him to be included in a matching database so that he could see if he has matches with other people with the same surname. It would also give him a haplogroup assignment. Haplogroups are branches of the human Y-tree. They all have slightly different origins, and some are more prevalent in Scandinavia than others. No test would prove or disprove that your OH is a Viking so if that's all you want to prove you would definitely be wasting your money. You might well find companies that will suggest your OH is a Viking but such claims are not based on any scientific evidence.
-
Devon, I have just finished reading the Mark Thomas article which I found very interesting and easy to understand. The comments which followed the article are also worth reading.
I was always pretty cynical about what DNA testing could tell us, and how believable it's claims were especially considering the commercial aspect and the fact that many of these companies are American, but I had recently 'come around' and thought it would be worth a try.
Now I am even more confused. :-\
-
Devon, I am sending you a PM. :)
-
Ruskie, I'll reply to you by PM but I just thought I'd answer briefly here in case anyone else has the same questions. There are many different companies that offer these tests. There are comparison charts in the ISOGG Wiki:
http://www.isogg.org/wiki
There are a few British companies but they are very expensive and the tests that they offer are not suitable for genealogy purposes as they don't test the right markers that you can use in a matching database. The best companies are Family Tree DNA and 23andMe, both of which are in America. Thousands of Brits have now tested with both these companies. Within the Guild of One-Name Studies nearly all our DNA projects are hosted at FTDNA, and a large percentage of these are led by project admins in the UK. Family Tree DNA offers the widest range of genetic genealogy tests. They sponsor the big DNA workshop at WDYTYA Live at Olympia every year. 23andMe does a health test but it also has lots of other features including a Relative Finder feature which allows you to find matches with genetic cousins. The 23andMe has only recently come down in price to an affordable level. I've done some blog posts on 23andMe which include screenshots:
http://cruwys.blogspot.co.uk/2012/12/23andme-test-now-down-to-99.html
A DNA test can give you some idea of the geographical origin of your Y-DNA line (males only) or mitochondrial DNA line (both males and females). This is based on comparisons with living people. You get a haplogroup assignment. A haplogroup is a branch of the human family tree. Some haplogroups are more prevalent in some regions than others. For example, Y-DNA haplogroup R1a is more often found in the north of Britain and in Scandinavian countries. That is a very different matter from declaring that someone is a Viking because they belong to haplogroup R1a. It's all much more complicated than that. However, it's a fascinating area and we all learn more as more people test and join the database. At Family Tree DNA there are haplogroup projects that you can join and people can go on and test for additional markers to refine their haplogroup. Some of the sub-branches within the haplogroups only date back to 1000 to 2000 years ago so you can see that eventually with enough data from archaeological evidence and ancient DNA it might be possible to pinpoint the origins of these branches much more precisely.
-
Devon, The Geno 2 test incorporates SNP results from the recent Walk the Y and 1000 Genomes projects and makes older tests pointless. FTDNA have withdrawn their deepclade test and I guess 23andme have reduced their prices perhaps because their test is out of date?
-
I did a Y-DNA37 test with FTDA. & am struggling to get my head round the results. I am getting hundreds of matches at the 12 marker level, only one at the 25 marker level & none at 37.
Here are my results for the 25 marker match and I wonder if they are significant or not worth worrying about. We have different surnames but strangely both family names which are fairly rare were prominent in the same small area a couple of hundred years ago.
Are you R1b Haplogroup? If so, totally ignore all of the 12 and 25 marker matches as you will match other R1bs who are not related to you within the last few thousand years. There is so little diffference between the markers of R1b people they "overlap" one another.
-
The Geno 2.0 test is useful if you want to know about your deep ancestry and if you want to see if you have any new Y-SNPs. The Geno 2.0 test has effectively replaced the old FTDNA deep clade test. You get over 12,000 Y-SNPs on the Geno chip.
The 23andMe test is of more interest if you're interested in the health aspects. It's not so good for the Y-SNPs. They've reduced the cost of their test so that they can increase the size of their database. They're aiming for one million users. The test is not out of date, but no doubt they will eventually offer a full genome sequence test.
You might like to have a look at the autosomal DNA testing comparison chart in the ISOGG Wiki:
http://www.isogg.org/wiki/Autosomal_DNA_testing_comparison_chart
-
May I jump in here and ask about the Geno 2.0 DNA test.
I understand this looks at your deep genetic family history for both the Y-DNA and mtDNA and that it gives you a percentage breakdown of your genetic ancestry e.g. 60% European, 30% South Asian, 10% African etc.
Now I understand the deep Y-DNA and mtDNA analysis will be based on your direct male and direct female lines respectively. So what happens to all the lines in between, are these that are used to calculate the percentages of your genetic ancestry and if so how do they do that.
And in short does a Geno 2.0 test accurately reflect your deep genetic past (within the constraints of present technology) or only a limited part of it.
Thank you.
-
Thank you for the explanation Devon. :)
-
Autosomal DNA tells you about "all the lines in between". There are four autosomal DNA tests on the market: 23andMe, Geno 2.0 from the Genographic Project, Family Finder from Family Tree DNA and AncestryDNA, Ancestry.com's autosomal DNA product. The Ancestry test is only available in the US. 23andMe and Geno 2.0 both include Y-DNA and mtDNA. With Family Finder the Y-DNA and mtDNA components have to be ordered separately. All four companies give you ethnicity percentages but none of them are particularly accurate or useful at present unless you're looking for traces of more exotic ancestry (eg, African or Indian). See this detailed blog post by CeCe Moore for comparisons:
http://www.yourgeneticgenealogist.com/2012/12/comparing-admixture-test-results-across.html
See also my blog posts here:
http://cruwys.blogspot.co.uk/search/label/Admixture%20tests
-
The Geno 2.0 test is useful if you want to know about your deep ancestry and if you want to see if you have any new Y-SNPs. The Geno 2.0 test has effectively replaced the old FTDNA deep clade test. You get over 12,000 Y-SNPs on the Geno chip.
The 23andMe test is of more interest if you're interested in the health aspects. It's not so good for the Y-SNPs. They've reduced the cost of their test so that they can increase the size of their database.
Agreed. Mostly. ;) Its probably a question of semantics, but at the rate that we are now finding new SNPs, that span the gap between surname times and ye olde ancient times, it is a bit of a misnomer to call it "Deep" ancestry anymore. We may be looking at being able to say that a person is related to one group of people from regions W within 500 yrs, another group from regions W,X within 1000 yrs, another group from W,X,Y within 1500, another from 2000, etc., within the next few years. Some subgroups uncovered by WTY and 1K Genomes can pretty much do this already.
-
Agreed. Mostly. ;) Its probably a question of semantics, but at the rate that we are now finding new SNPs, that span the gap between surname times and ye olde ancient times, it is a bit of a misnomer to call it "Deep" ancestry anymore. We may be looking at being able to say that a person is related to one group of people from regions W within 500 yrs, another group from regions W,X within 1000 yrs, another group from W,X,Y within 1500, another from 2000, etc., within the next few years. Some subgroups uncovered by WTY and 1K Genomes can pretty much do this already.
You're quite right and in fact this is indeed already happening. Both the Barton and Irvine DNA projects have private SNPs that arose in the last 500 years or so. Many of the new SNPs are hovering around the 1500 years mark and are getting tantalisingly closer to the beginnings of surnames. At the moment it's only advanced users who are getting this information by joining haplogroup projects and testing for the appropriate Y-SNPs. The companies are not doing the analysis. It's all being done by citizen scientists. There is a small army of volunteers collecting Geno 2.0 Y-SNP data. They are trying to identify the correct position of all the unplaced SNPs on the Geno chip in their respective haplogroups:
http://www.isogg.org/wiki/Genographic_Project#What_to_do_with_your_Geno_2.0_results
-
It's all being done by citizen scientists.
Sigh, We used to call them DNA junkies but guess we have to move with the times. ;D
-
@ DevonCruwys
Thank you for the reply and links, they were very helpful.
Don't think a Geno 2.0 is for me at the moment. I'll just wait for more people with my surname to do a Y-DNA test
-
Oh that's no good! :( My OH keeps saying he is a Viking. I keep telling him he isn't. I was going to buy him a test to prove that I was right. ;D Will I be wasting my money? :(
No test can provide you with a concrete answer, of course, but they can hint at the British Isles origins of your other half. My ancestry is predominately English with lots of English surnames, but I also have a sprinkle of Welsh surnames, but - as of yet - no Welsh ancestors found, and the tests have simply confirmed all this. McDonald even slapped me right on the English/Welsh border in two separate occasions.
I'd say the tests provided by FTDNA and 23andme are well worth investing in.
-
Thanks for that.
I intend to get a test for him in the very near future. :)
-
Thanks for starting this thread Rena .. It has been fascinating and most informative . Thank you for the helpful links and explanations everyone. I took the Family Finder DNA Test with FTDNA at the WDYTYA show a few weeks ago and am looking forward to seeing what I learn from the results in another 6 weeks time. I no doubt will be back on this board to ask questions when that happens .
Poll :)
-
I know it's rather late in the day now but I've written a blog post explaining some of the problems with this programme. I've also discussed the wider issue of concerns relating to the BBC's handling of this whole affair:
http://cruwys.blogspot.co.uk/2014/01/britainsdna-bbc-and-eddie-izzard.html