DNA testing - genetic genealogy

[DevonCruwys]

Hi Pippa

The new autosomal DNA tests (Family Finder from Family Tree DNA and Relative Finder from 23andME) would give you the answer you require. I'm struggling to get my head round your relationships but if you're no more than third cousins then you would have matching shared segments of autosomal DNA. Once you get out as far as fourth cousins then there is only a 50% possibility that the match will be detected. (In other words, a positive result would confirm the relationship but a negative result would not necessarily prove that you are not related.)

On average third cousins share 0.78% of their DNA and fourth cousins share 0.20% but the percentages can vary because of the random way in which autosomal DNA is inherited.

FTDNA is probably the best company to test with as they have a database full of genealogists so as a bonus you will probably get matches with other genetic cousins. 23andMe focus mostly on health tests and the matches often don't respond. In case it's of any help here is my write-up of the Family Finder test:

http://cruwys.blogspot.com/2010/04/new-family-finder-test-from-ftdna.html

I've also tested at 23andMe.

Debbie


 

[Tisy]

Hi Debbie,

If you would like a link to Steve Gilbert's site, contact me privately.

In regard to the autosomal test - anything you have to offer in the way of advice would be appreciated.  I have joined ISOGG, and through them the "DNA-Newbie" group on Yahoo;  they are discussing the autosomal stuff at the moment, but I am really struggling to understand it.

Our closest Y-DNA match is a genetic distance 4 match which originated in Derbyshire - my ancestor was born in Barnsley, Yorkshire, so it looks very likely that we are related somewhere along the line.  However, I have been advised that this could be anything from 7 - 20 generations back, so would probably not be any good for the autosomal test.

Tisy

[Pippakit]

Thank you for your reply Debbie.

I know that the relationship I posted is confusing, but you are right - we are 3rd cousins. So it looks like we could establish once and for all if we are really related.

PippaKit

[Navn]

<snip>

Y-DNA (Y-chromosome) testing has only been available in the last ten years but those of us who are running surname projects, including many of my colleagues from the Guild of One-Name Studies, are already beginning to see the benefits. Family Tree DNA has the largest Y-DNA database in the world with almost 200,000 Y- chromosome DNA results. Your chances of success really depend on the composition of your surname project. Some projects (such as my own) have reached critical mass and any new testee stands a very good chance of getting a match. Others are only just starting out. There are also many surname projects which are dominated by Americans. If this is the case it's always worth e-mailing the project administrator to see if the project will sponsor a test for a UK participant. Some US-led projects (eg, PHILLIPS) have a standing offer to provide free tests for UK participants if a pedigree is provided. As a result the Phillips project now has a relatively large number of UK testees;

<snip>

(my emphasis)

This is what happened in my case, in that I was sponsered by someone in Canada.

[helvissa]

This thread has been very helpful.

I know someone who was adopted not long after birth in the UK and has a name for his father which his birth mother gave him, but no other info (he was an American serviceman). He was adopted at a time that getting the paperwork from his adoption is very difficult - it may even have been chucked away (how kind!). And of course, it's not guaranteed that there'll be any info about his father on the paperwork.

Rather than use DNA to track down his father, he's is hoping that the DNA could at least give him an idea of where his extended family were from and maybe find distant cousins, even just a sense of "who am I?", which I'm sure anyone who's obsessed with doing their family trees can appreciate! As a bloke, he's quite lucky presumably and can do a Y-chromosome test to find this out. And given that his father was American, that might help too given the popularity with DNA testing in the US.

The only thing is, there's no paper as such (unless he can find those adoption records) to prove his father's surname. Would that present a problem with him doing the DNA genealogy?

[DevonCruwys]

Helvissa,

This is exactly the sort of scenario for which DNA testing is so useful. So much depends on the databases and whether or not the right people have tested. A match will not necessarily prove the surname, as people can have matches at 37 and even 67 markers with a number of different surnames, but it should give him some useful clues. There is of course no guarantee of a match but most people have low-resolution matches at 12- and 25-markers which would give him some sense of identity. The haplogroup designation would also help, as some haplogroups are associated with particular geographical regions.

There is a very large project at Family Tree DNA for adoptees:

http://www.familytreedna.com/public/adopted/default.aspx

Your friend would really need a 67-marker test.

There is a well publicised story of a man by the name Dick Hill in America who discovered the identity of his real father through DNA testing. You can read his story here:

http://www.mlive.com/news/grand-rapids/index.ssf/2009/06/rockford_man_uses_dna_testing.html

Dick was inspired by his success to set up his own website to advise adoptees on the subject of DNA testing:

http://www.dna-testing-adviser.com/index.html

[helvissa]

that's really interesting - thank you!

There's a project on the site you recommended for variations of the surname he has for his father, so I suppose that might be worth looking into. Presumably you can be in a couple of groups?

The links are great - I shall get him to come and have a read here.

Thanks!

[DevonCruwys]

Helvissa

He can join as many projects as he likes. He could even be a number of different surname projects at the same time. There are also lots of haplogroup projects. He's best off ordering a test through the adoptees project. There is usually a sale in December so if he wanted to go ahead that might be the best time to order a test.

[helvissa]

Great advice, thanks!