BBC: Eddie Izzard follows his DNA Trail

[Ruskie]

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.

[Ruskie]

Devon, I am sending you a PM. 

[DevonCruwys]

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.

[supermoussi]

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?

[supermoussi]

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.

[DevonCruwys]

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

[davidft]

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.

[Ruskie]

Thank you for the explanation Devon. 

[DevonCruwys]

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