DNA Database size.

[Braeseke]

With all these advertisers of DNA testing about, Ancestry, Oxford, FamilyTreeDNA to name but a few, how can I find out what sizes their databases are?

Isn't it better to have a test done by the company that has the largest databases, that way there's more likelihood of a comparable match?

[arthurk]

The company with the largest database might be the one to go for, but that's not the only consideration. Different companies offer tests on a different number of markers, and generally speaking, the more markers you have tested the better. But to answer your question, some companies have public databases of their results and can give a figure, or you might have to ask them directly. One large company, I believe, isn't shy about saying how much bigger they are than all the others put together.

However, size isn't everything. If you're a male and looking at a yDNA test (in order to corroborate a direct male line), it may be equally important to consider whether there's a project for your surname hosted by one of the companies and join that - usually with a reduction in the normal fee. If you're looking at a mtDNA test (direct female line, which can include a male at the end but none of his descendants) I think some companies might allow you to join a surname project that matches any of the surnames in your direct female ancestry, but you'd need to check this with them.

Hope this helps - ask again if it doesn't.
Arthur

[Braeseke]

Thanks very much for the reply Arthur.

I am looking into (and reading up on) having a DNA test for myself and a test for another chap. I want to find out if we share the same grandfather/great grandfather. I would also like to find out if there might be other (near) matches, etc out there.

I don't know if there currently is a what you could call 'Best' DNA testing company out there, would you know or are all the companies pretty similar in what they offer, subject to the number of markers they test?

[arthurk]

Even if I could say which is the "best" testing company, I suspect it might be against forum rules to tell you here. There's a group at Yahoo called DNA-Newbie (I'm a member) where you might get an answer, or at least a variety of opinions. I've a feeling that there might have been one company that wasn't very well regarded not too long ago, but even if I could remember clearly, I don't think I'd post the information publicly here.

One possible consideration beyond what I wrote before is how deep you want to have your DNA analysed: for the scenario you paint, more or less any company would be able to do the tests, but some companies now also offer a set of further tests which are claimed to shed more light on where your ancestors were thousands of years ago - though that's more about anthropology than genealogy.

Sorry I can't say anything more constructive - my personal experience is limited to one company, which I was steered to by a project administrator, and I haven't had any of the deeper tests done. A final thought - have a look online for the International Society of Genetic Genealogy (ISOGG), which is the body behind the Yahoo group I mentioned - their website has a lot of useful information.

Arthur

[Braeseke]

Many thanks again for the info Arthur. I shall wonder off and look into your suggestions. :D

[Border Reiver]

I have been tested by Family Tree DNA. I tested for 37 markers which I'm told is sufficient enough to test for a common paternal ancestor. They do, however, test for more markers should you wish.

I found they also have the largest database and charged half the price of Oxford Ancestors, who only test for 12 markers!